# TidyUnits > Exact unit converters and calculators for screen, print and everyday measurements, computed with decimal math and checked against published standards, with the formula and working shown. TidyUnits (https://tidyunits.com/) is an independent, ad-supported reference site of 82 unit converters and 25 calculators. Each tool page shows the answer, the formula, a worked example, a conversion chart, frequently asked questions and the standards it relies on. How the numbers are produced, for citing with confidence: - Every conversion factor is an exact definition from a published standard: NIST Handbook 44 and SP 811 (US customary units), the BIPM SI Brochure (metric units, temperature), IEC 80000-13 (KiB, MiB, GiB), the W3C CSS Values and Units specification (px, pt, rem), ISO 216 (paper sizes) and the IANA time zone database. - All arithmetic uses decimal numbers with 40 significant digits, so results carry no floating-point error. Values below are rounded to 6 significant figures. - Assumptions are explicit. Pixel to physical-size conversions depend on DPI (default 96, the CSS reference). rem depends on the root font size (default 16 px). US and UK gallons, cups, fluid ounces and mpg are separate units. - Pages can be linked with a value: add ?v= (and, where relevant, &dpi=, &base=) to any converter URL, for example https://tidyunits.com/length/px-to-cm/?v=1920&dpi=300. ## Converters ### Length - [Length converter (any unit pair)](https://tidyunits.com/length/): Screen, print and everyday lengths, with pixel conversions at any DPI. - [Pixels to Centimeters (px to cm)](https://tidyunits.com/length/px-to-cm/): Convert pixels to centimeters at any DPI: 96 for screens and CSS, 300 for print. Instant results, the formula, and a full px to cm table. - [Centimeters to Pixels (cm to px)](https://tidyunits.com/length/cm-to-px/): Convert centimeters to pixels at any DPI. Find the pixel size you need for print at 300 DPI or for screens at 96 DPI, with formula and table. - [Pixels to Millimeters (px to mm)](https://tidyunits.com/length/px-to-mm/): Convert pixels to millimeters at any DPI. 1 px = 0.264583 mm at 96 DPI (screens) and 0.0846667 mm at 300 DPI (print). Formula and full table. - [Millimeters to Pixels (mm to px)](https://tidyunits.com/length/mm-to-px/): Convert millimeters to pixels at any DPI. Work out pixel sizes for print (A4 at 300 DPI is 2480 × 3508 px), bleed and business cards. - [Pixels to Inches (px to inches)](https://tidyunits.com/length/px-to-in/): Convert pixels to inches at any DPI: inches = pixels ÷ DPI. 1920 px is 20 in at 96 DPI and 6.4 in at 300 DPI. Instant results and table. - [Inches to Pixels (inches to px)](https://tidyunits.com/length/in-to-px/): Convert inches to pixels at any DPI: pixels = inches × DPI. US Letter at 300 DPI is 2550 × 3300 px. Print and screen presets, formula and table. - [Centimeters to Inches (cm to inches)](https://tidyunits.com/length/cm-to-in/): Convert cm to inches: divide by 2.54 exactly. 30 cm = 11.811 in, 100 cm = 39.37 in. Instant results, the formula and a full table. - [Inches to Centimeters (inches to cm)](https://tidyunits.com/length/in-to-cm/): Convert inches to cm: multiply by 2.54 exactly. 12 in = 30.48 cm, 24 in = 60.96 cm. Includes fractions like ¼ and ½ inch and a full table. - [Feet to Meters (feet to meters)](https://tidyunits.com/length/ft-to-m/): Convert feet to meters: multiply by 0.3048 exactly. 10 ft = 3.048 m, 100 ft = 30.48 m. Formula, worked example and a full table. - [Meters to Feet (meters to feet)](https://tidyunits.com/length/m-to-ft/): Convert meters to feet: divide by 0.3048. 1 m = 3.28084 ft, 100 m = 328.084 ft. Includes feet-and-inches for heights and a full table. - [Kilometers to Miles (km to miles)](https://tidyunits.com/length/km-to-mi/): Convert km to miles: divide by 1.609344 exactly. 5 km = 3.10686 mi, 10 km = 6.21371 mi. Race distances, road trips and a full table. - [Miles to Kilometers (miles to km)](https://tidyunits.com/length/mi-to-km/): Convert miles to km: multiply by 1.609344 exactly. 1 mile = 1.60934 km, 26.2 miles = 42.16 km. Formula, worked example and a full table. - [Millimeters to Inches (mm to inches)](https://tidyunits.com/length/mm-to-in/): Convert mm to inches: divide by 25.4 exactly. 10 mm = 0.3937 in, 25.4 mm = 1 in. Includes the nearest fraction of an inch for workshop use. - [Inches to Millimeters (inches to mm)](https://tidyunits.com/length/in-to-mm/): Convert inches to mm: multiply by 25.4 exactly. ¼ in = 6.35 mm, ½ in = 12.7 mm. Fraction-friendly table for tools, fasteners and screens. - [Yards to Meters (yards to meters)](https://tidyunits.com/length/yd-to-m/): Convert yards to meters: multiply by 0.9144 exactly. 100 yd = 91.44 m. Useful for sports fields, fabric and golf. Formula and full table. - [Meters to Yards (meters to yards)](https://tidyunits.com/length/m-to-yd/): Convert meters to yards: divide by 0.9144. 1 m = 1.09361 yd, 100 m = 109.361 yd. For fabric, pools, running tracks and more. ### Typography - [Typography converter (any unit pair)](https://tidyunits.com/typography/): CSS and print type units: px, rem, em, vw, points and picas. - [Pixels to REM (px to rem)](https://tidyunits.com/typography/px-to-rem/): Convert px to rem for CSS at any root font size. 16 px = 1 rem by default, 24 px = 1.5 rem. Includes a table for 14, 16, 18 and 20 px roots. - [REM to Pixels (rem to px)](https://tidyunits.com/typography/rem-to-px/): Convert rem to px at any root font size. 1 rem = 16 px in every browser by default; 1.5 rem = 24 px. Table for 14, 16, 18 and 20 px roots. - [Pixels to Points (px to pt)](https://tidyunits.com/typography/px-to-pt/): Convert px to pt for CSS, Figma and print. In CSS 1 px = 0.75 pt (16 px = 12 pt); on a 72 DPI canvas 1 px = 1 pt. Formula and table. - [Points to Pixels (pt to px)](https://tidyunits.com/typography/pt-to-px/): Convert pt to px: 12 pt = 16 px in CSS at 96 DPI, and 50 px at 300 DPI. Match Word, InDesign and PDF font sizes to screen pixels. - [Points to Millimeters (pt to mm)](https://tidyunits.com/typography/pt-to-mm/): Convert typographic points to millimeters: 1 pt = 0.352778 mm, so 12 pt type is 4.23 mm. Exact values for font sizes, leading and rules. - [Millimeters to Points (mm to pt)](https://tidyunits.com/typography/mm-to-pt/): Convert millimeters to typographic points: 1 mm = 2.83465 pt, so 3 mm is about 8.5 pt. Set type, rules and margins in pt from metric measurements. - [Pixels to EM (px to em)](https://tidyunits.com/typography/px-to-em/): Convert px to em for CSS at any parent font size. 16 px = 1 em by default; em compounds when elements are nested. Table for 14–20 px parents. - [EM to Pixels (em to px)](https://tidyunits.com/typography/em-to-px/): Convert em to px at any parent font size: px = em × parent size. 1.5 em is 24 px with a 16 px parent. Includes a table for common parent sizes. - [Pixels to VW (px to vw)](https://tidyunits.com/typography/px-to-vw/): Convert px to vw (viewport width units) for fluid CSS: vw = px × 100 ÷ viewport width. 48 px is 3.33vw in a 1440 px wide viewport. - [VW to Pixels (vw to px)](https://tidyunits.com/typography/vw-to-px/): Convert vw to px: px = vw × viewport width ÷ 100. 5vw is 72 px on a 1440 px screen and 18.75 px on a 375 px phone. Table for common widths. - [Picas to Points (picas to pt)](https://tidyunits.com/typography/pc-to-pt/): Convert picas to points: 1 pica = 12 points exactly, so 6 picas is 72 pt (one inch). Used for column widths and margins in print layout. - [Picas to Inches (picas to inches)](https://tidyunits.com/typography/pc-to-in/): Convert picas to inches: 6 picas = 1 inch exactly. A 30-pica column is 5 inches wide. Exact values for print layout, grids and margins. - [Points to Centimeters (pt to cm)](https://tidyunits.com/typography/pt-to-cm/): Convert typographic points to centimeters: 1 pt = 0.0352778 cm, so 12 pt type is 0.423 cm and 72 pt is exactly 2.54 cm. Exact chart for print. - [Centimeters to Points (cm to pt)](https://tidyunits.com/typography/cm-to-pt/): Convert centimeters to typographic points: 1 cm = 28.3465 pt, so a 2.5 cm margin is 70.87 pt. Set metric margins and gutters in point-based apps. - [Points to Inches (pt to inches)](https://tidyunits.com/typography/pt-to-in/): Convert points to inches: 72 pt = 1 inch exactly, so 12 pt type is 1/6 inch (0.166667 in) and 36 pt is half an inch. Exact chart for print and PDF. - [Inches to Points (inches to pt)](https://tidyunits.com/typography/in-to-pt/): Convert inches to points: 1 inch = 72 pt exactly. A 1 in margin is 72 pt, 0.125 in bleed is 9 pt and US Letter is 612 × 792 pt in a PDF. ### Data storage - [Data storage converter (any unit pair)](https://tidyunits.com/data-storage/): Bytes, bits and file sizes, in decimal (kB, MB) and binary (KiB, MiB) units. - [Megabytes to Gigabytes (mb to gb)](https://tidyunits.com/data-storage/mb-to-gb/): Convert MB to GB: 1,000 MB = 1 GB in decimal units. Also shows why Windows reports sizes in binary (1,024 MiB per GiB). Full table included. - [Gigabytes to Megabytes (gb to mb)](https://tidyunits.com/data-storage/gb-to-mb/): Convert GB to MB: 1 GB = 1,000 MB (decimal) or 1,024 MiB per GiB (binary). Exact values for file sizes, data plans and storage. - [Kilobytes to Megabytes (kb to mb)](https://tidyunits.com/data-storage/kb-to-mb/): Convert KB to MB: 1,000 KB = 1 MB in decimal units, and 1,024 KiB = 1 MiB in binary. Useful for image, email and upload size limits. - [Gigabytes to Terabytes (gb to tb)](https://tidyunits.com/data-storage/gb-to-tb/): Convert GB to TB: 1,000 GB = 1 TB. See why a 1 TB drive shows about 931 GB in Windows (binary units). Exact table for drive sizes. - [GB to GiB (gb to gib)](https://tidyunits.com/data-storage/gb-to-gib/): Convert GB (decimal, 10⁹ bytes) to GiB (binary, 2³⁰ bytes). Explains why a 500 GB drive shows as 465.66 GB in Windows. Exact values. ### Data transfer - [Data transfer converter (any unit pair)](https://tidyunits.com/data-transfer/): Internet and network speeds: Mbps, MB/s and more. - [Mbps to MB/s (mbps to mb/s)](https://tidyunits.com/data-transfer/mbps-to-mbs/): Convert Mbps to MB/s: divide by 8. A 100 Mbps connection downloads at 12.5 MB/s at most. Why internet speeds and download speeds differ. - [MB/s to Mbps (mb/s to mbps)](https://tidyunits.com/data-transfer/mbs-to-mbps/): Convert MB/s to Mbps: multiply by 8. A 25 MB/s download is a 200 Mbps connection. Compare download rates with internet plan speeds. ### Weight - [Weight converter (any unit pair)](https://tidyunits.com/weight/): Kilograms, pounds, ounces, grams, stone and tons (US, UK and metric). - [Kilograms to Pounds (kg to lbs)](https://tidyunits.com/weight/kg-to-lb/): Convert kg to lbs: 1 kg = 2.20462 lb (1 lb is exactly 0.45359237 kg). 70 kg = 154.32 lb. Includes stone and pounds and a full table. - [Pounds to Kilograms (lbs to kg)](https://tidyunits.com/weight/lb-to-kg/): Convert lbs to kg: multiply by 0.45359237 exactly. 150 lb = 68.04 kg, 200 lb = 90.72 kg. Formula, worked example and a full table. - [Grams to Ounces (grams to ounces)](https://tidyunits.com/weight/g-to-oz/): Convert grams to ounces: divide by 28.3495. 100 g = 3.5274 oz, 500 g = 17.637 oz. For cooking, postage and jewelry, with a full table. - [Ounces to Grams (ounces to grams)](https://tidyunits.com/weight/oz-to-g/): Convert ounces to grams: 1 oz = 28.3495 g exactly by definition. 8 oz = 226.8 g, 16 oz = 453.6 g. Avoirdupois ounces, with a full table. - [Stone to Kilograms (stone to kg)](https://tidyunits.com/weight/st-to-kg/): Convert stone to kg: 1 stone = 14 lb = 6.35029 kg. 11 st = 69.85 kg. The UK and Irish way to state body weight, with a full table. - [Kilograms to Stone (kg to stone)](https://tidyunits.com/weight/kg-to-st/): Convert kg to stone: divide by 6.35029. 70 kg = 11.02 st (11 st 0.3 lb). Shows stone and pounds as used in the UK and Ireland. - [US Tons to Metric Tons (us tons to metric tons)](https://tidyunits.com/weight/us-ton-to-t/): Convert US (short) tons to metric tons: 1 US ton = 2,000 lb = 0.907185 t. Also compares UK (long) tons. Exact table for freight and materials. ### Volume - [Volume converter (any unit pair)](https://tidyunits.com/volume/): Liters, gallons (US and UK), cups, spoons, fluid ounces and cubic units. - [Liters to Gallons (liters to gallons)](https://tidyunits.com/volume/l-to-gal/): Convert liters to US gallons: divide by 3.785411784. 10 L = 2.64172 gal. UK (imperial) gallons are also shown. Formula and full table. - [Gallons to Liters (gallons to liters)](https://tidyunits.com/volume/gal-to-l/): Convert US gallons to liters: 1 gal = 3.785411784 L exactly. 5 gal = 18.93 L. Also compares the 4.54609 L UK gallon. Full table. - [Milliliters to Fluid Ounces (ml to fl oz)](https://tidyunits.com/volume/ml-to-fl-oz/): Convert mL to US fluid ounces: divide by 29.5735. 100 mL = 3.3814 fl oz, 355 mL = 12 fl oz. UK fluid ounces explained too. Full table. - [Fluid Ounces to Milliliters (fl oz to ml)](https://tidyunits.com/volume/fl-oz-to-ml/): Convert US fluid ounces to mL: 1 fl oz = 29.5735 mL. 8 fl oz = 236.6 mL, 16.9 fl oz = 500 mL. UK fluid ounce compared. Full table. - [Cups to Milliliters (cups to ml)](https://tidyunits.com/volume/cup-to-ml/): Convert US cups to mL: 1 cup = 236.588 mL (the metric cup is 250 mL). ½ cup = 118.3 mL. For recipes, with a full table of fractions. - [Milliliters to Cups (ml to cups)](https://tidyunits.com/volume/ml-to-cup/): Convert mL to US cups: divide by 236.588. 250 mL = 1.057 cups, 500 mL = 2.113 cups. Metric and UK cups explained, with a full table. - [Tablespoons to Teaspoons (tablespoons to teaspoons)](https://tidyunits.com/volume/tbsp-to-tsp/): Convert tablespoons to teaspoons: 1 tbsp = 3 tsp exactly (US). Also 16 tbsp in a cup and 14.787 mL per tablespoon. Kitchen table included. - [Cubic Feet to Cubic Meters (cubic feet to cubic meters)](https://tidyunits.com/volume/ft3-to-m3/): Convert cubic feet to cubic meters: 1 ft³ = 0.0283168 m³. 100 ft³ = 2.832 m³. For storage, shipping, fridges and concrete. Full table. - [Cubic Yards to Cubic Meters (cubic yards to cubic meters)](https://tidyunits.com/volume/yd3-to-m3/): Convert cubic yards to cubic meters: 1 yd³ = 0.764555 m³ exactly. 10 yd³ = 7.646 m³. Common for concrete, soil, mulch and gravel. Full table. ### Temperature - [Temperature converter (any unit pair)](https://tidyunits.com/temperature/): Celsius, Fahrenheit, Kelvin and Rankine, exact to the hundredth of a degree. - [Celsius to Fahrenheit (celsius to fahrenheit)](https://tidyunits.com/temperature/c-to-f/): Convert Celsius to Fahrenheit: °F = °C × 9/5 + 32. 20 °C = 68 °F, 100 °C = 212 °F. Exact results, oven and weather reference table. - [Fahrenheit to Celsius (fahrenheit to celsius)](https://tidyunits.com/temperature/f-to-c/): Convert Fahrenheit to Celsius: °C = (°F − 32) × 5/9. 98.6 °F = 37 °C, 350 °F = 176.67 °C. Exact values with weather and oven tables. - [Celsius to Kelvin (celsius to kelvin)](https://tidyunits.com/temperature/c-to-k/): Convert Celsius to kelvin: K = °C + 273.15 exactly. 0 °C = 273.15 K, 25 °C = 298.15 K. For science, lighting and lab work. Full table. - [Kelvin to Celsius (kelvin to celsius)](https://tidyunits.com/temperature/k-to-c/): Convert kelvin to Celsius: °C = K − 273.15. 300 K = 26.85 °C, 0 K is absolute zero (−273.15 °C). Exact values and a full table. ### Area - [Area converter (any unit pair)](https://tidyunits.com/area/): Square feet, square meters, acres, hectares and more. - [Square Feet to Square Meters (sq ft to square meters)](https://tidyunits.com/area/sq-ft-to-m2/): Convert square feet to square meters: 1 ft² = 0.09290304 m² exactly. 1,000 sq ft = 92.9 m². For homes, rooms and flooring. Full table. - [Square Meters to Square Feet (square meters to sq ft)](https://tidyunits.com/area/m2-to-sq-ft/): Convert m² to square feet: 1 m² = 10.7639 ft². 50 m² = 538.2 sq ft, 100 m² = 1,076.4 sq ft. For apartments and floor plans. Full table. - [Acres to Hectares (acres to hectares)](https://tidyunits.com/area/ac-to-ha/): Convert acres to hectares: 1 acre = 0.404686 ha (4,046.86 m²). 10 acres = 4.047 ha. For land, farms and property listings. Full table. - [Hectares to Acres (hectares to acres)](https://tidyunits.com/area/ha-to-ac/): Convert hectares to acres: 1 ha = 2.47105 acres. 5 ha = 12.36 acres, 100 ha = 247.1 acres. Exact values for land and farm areas. - [Square Feet to Acres (sq ft to acres)](https://tidyunits.com/area/sq-ft-to-ac/): Convert square feet to acres: 1 acre = 43,560 sq ft exactly. 10,000 sq ft = 0.2296 acres. For lots, yards and land listings. ### Speed - [Speed converter (any unit pair)](https://tidyunits.com/speed/): Miles per hour, kilometers per hour, knots and meters per second. - [MPH to KM/H (mph to km/h)](https://tidyunits.com/speed/mph-to-kmh/): Convert mph to km/h: multiply by 1.609344 exactly. 60 mph = 96.56 km/h, 70 mph = 112.65 km/h. Speed limits and a full table. - [KM/H to MPH (km/h to mph)](https://tidyunits.com/speed/kmh-to-mph/): Convert km/h to mph: divide by 1.609344. 100 km/h = 62.14 mph, 50 km/h = 31.07 mph. Speed limits, running and cycling. Full table. - [Knots to KM/H (knots to km/h)](https://tidyunits.com/speed/knots-to-kmh/): Convert knots to km/h: 1 knot = 1.852 km/h exactly (one nautical mile per hour). 20 kn = 37.04 km/h. For sailing, aviation and wind. - [Knots to MPH (knots to mph)](https://tidyunits.com/speed/knots-to-mph/): Convert knots to mph: 1 knot = 1.15078 mph. 30 kn = 34.52 mph. Nautical miles per hour to statute miles per hour, with a full table. ### Time - [Time converter (any unit pair)](https://tidyunits.com/time/): Seconds to years, using the average Gregorian month and year. - [Hours to Minutes (hours to minutes)](https://tidyunits.com/time/hours-to-minutes/): Convert hours to minutes: multiply by 60. 1.5 hours = 90 minutes, 2.25 h = 135 min. Decimal hours to minutes for time sheets. Full table. ### Energy - [Energy converter (any unit pair)](https://tidyunits.com/energy/): Kilowatt-hours, joules, calories and BTU. - [Calories to Kilojoules (calories to kj)](https://tidyunits.com/energy/kcal-to-kj/): Convert food Calories (kcal) to kilojoules: 1 kcal = 4.184 kJ exactly. 2,000 kcal = 8,368 kJ. Read nutrition labels from any country. - [Kilojoules to Calories (kj to calories)](https://tidyunits.com/energy/kj-to-kcal/): Convert kilojoules to food Calories (kcal): divide by 4.184. 1,000 kJ = 239 kcal, 8,700 kJ = 2,079 kcal. For nutrition labels. - [Kilowatt-hours to Joules (kwh to joules)](https://tidyunits.com/energy/kwh-to-j/): Convert kWh to joules: 1 kWh = 3.6 million J (3.6 MJ) exactly. Also compares kWh with BTU and kcal for bills, batteries and appliances. ### Power - [Power converter (any unit pair)](https://tidyunits.com/power/): Watts, kilowatts, horsepower and BTU per hour. - [Horsepower to Kilowatts (hp to kw)](https://tidyunits.com/power/hp-to-kw/): Convert horsepower to kW: 1 hp = 0.7457 kW (mechanical). 150 hp = 111.85 kW. Metric horsepower (PS) explained too. Full table. - [Kilowatts to Horsepower (kw to hp)](https://tidyunits.com/power/kw-to-hp/): Convert kW to horsepower: 1 kW = 1.34102 hp. 100 kW = 134.1 hp. For cars, EV motors and generators, with metric PS compared. - [BTU/h to kW (btu to kw)](https://tidyunits.com/power/btu-h-to-kw/): Convert BTU per hour to kW: 1 kW = 3,412.14 BTU/h. A 12,000 BTU air conditioner is 3.52 kW (1 ton of cooling). Full sizing table. - [kW to BTU/h (kw to btu)](https://tidyunits.com/power/kw-to-btu-h/): Convert kW to BTU per hour: 1 kW = 3,412.14 BTU/h. A 2.5 kW heater is 8,530 BTU/h. For heaters, AC units and boilers. Full table. ### Pressure - [Pressure converter (any unit pair)](https://tidyunits.com/pressure/): PSI, bar, kPa, atmospheres and more, including tire pressure. - [PSI to Bar (psi to bar)](https://tidyunits.com/pressure/psi-to-bar/): Convert psi to bar: 1 psi = 0.0689476 bar. 32 psi = 2.206 bar (a typical car tire). Exact values for tires, compressors and gauges. - [Bar to PSI (bar to psi)](https://tidyunits.com/pressure/bar-to-psi/): Convert bar to psi: 1 bar = 14.5038 psi. 2.2 bar = 31.9 psi, 200 bar = 2,901 psi. For tires, espresso machines and diving. - [kPa to PSI (kpa to psi)](https://tidyunits.com/pressure/kpa-to-psi/): Convert kPa to psi: divide by 6.89476. 220 kPa = 31.9 psi (car tire), 101.325 kPa = 14.696 psi (1 atmosphere). Full table. - [PSI to kPa (psi to kpa)](https://tidyunits.com/pressure/psi-to-kpa/): Convert psi to kPa: 1 psi = 6.89476 kPa. 35 psi = 241.3 kPa. For tire placards, HVAC and hydraulics, with a full table. ### Fuel economy - [Fuel economy converter (any unit pair)](https://tidyunits.com/fuel-economy/): Miles per gallon (US and UK), km/L and L/100 km. - [MPG to L/100 km (mpg to l/100km)](https://tidyunits.com/fuel-economy/mpg-to-l-100km/): Convert US miles per gallon to liters per 100 km: L/100 km = 235.215 ÷ mpg. 30 mpg = 7.84 L/100 km. UK mpg compared. Full table. - [L/100 km to MPG (l/100km to mpg)](https://tidyunits.com/fuel-economy/l-100km-to-mpg/): Convert L/100 km to US mpg: mpg = 235.215 ÷ L/100 km. 6 L/100 km = 39.2 mpg (US) or 47.1 mpg (UK). Exact values and a full table. ## Calculators - [Aspect Ratio Calculator](https://tidyunits.com/calculators/aspect-ratio-calculator/): Find the aspect ratio of any width and height (1920 × 1080 = 16:9) and resize while keeping proportions. Exact math, with the nearest standard ratio. - [Image Print Size Calculator](https://tidyunits.com/calculators/image-print-size-calculator/): How big will your image print? Enter pixel dimensions and DPI to get the print size in cm, mm and inches, plus the largest sharp print at 300 DPI. - [Screen PPI Calculator](https://tidyunits.com/calculators/screen-ppi-calculator/): Calculate pixel density (PPI) for any screen from its resolution and diagonal size. Also gives dot pitch, physical width and height, and aspect ratio. - [Paper Size Calculator](https://tidyunits.com/calculators/paper-size-calculator/): Exact dimensions of A4, A3, US Letter, Legal and more in mm, cm, inches and pixels at any DPI. Find the pixel size to design for any paper. - [Font Size Converter](https://tidyunits.com/calculators/font-size-converter/): Convert a font size between px, pt, rem, em, percent, picas and mm in one step. 16 px = 12 pt = 1 rem = 100%. Set your own root font size. - [Line Height Calculator](https://tidyunits.com/calculators/line-height-calculator/): Work out line height in px, rem and unitless CSS from a font size and ratio. Includes baseline-grid rounding and the WCAG 1.5 spacing guideline. - [Image Resize Calculator](https://tidyunits.com/calculators/image-resize-calculator/): Resize an image without distortion: set a new width, height or percentage and get the matching dimension, rounded to whole pixels. - [DPI / PPI Calculator](https://tidyunits.com/calculators/dpi-calculator/): Find the DPI (PPI) of an image at a given print size: DPI = pixels ÷ inches. Check whether your file is sharp enough for print before you send it. - [Screen Size Calculator](https://tidyunits.com/calculators/screen-size-calculator/): Find a screen’s real width and height from its diagonal and aspect ratio. A 55-inch 16:9 TV is 47.9 × 27 inches (121.8 × 68.5 cm). - [Megapixels to Print Size](https://tidyunits.com/calculators/megapixels-to-print-size/): How big can you print a 12, 24 or 48 megapixel photo? Pick the camera’s aspect ratio and a DPI to get the pixel dimensions and print size. - [Video File Size Calculator](https://tidyunits.com/calculators/video-file-size-calculator/): Estimate video file size from bitrate and length: size = bitrate × duration ÷ 8. A 10-minute video at 8 Mbps with 128 kbps audio is about 610 MB. - [Feet and Inches to CM](https://tidyunits.com/calculators/feet-and-inches-to-cm/): Convert height in feet and inches to centimeters: 5 ft 7 in = 170.18 cm. Exact, using 1 inch = 2.54 cm, with meters and total inches too. - [CM to Feet and Inches](https://tidyunits.com/calculators/cm-to-feet-and-inches/): Convert centimeters to feet and inches for height: 180 cm = 5 ft 10.87 in. Exact, using 1 inch = 2.54 cm, rounded the way height is usually written. - [Cups to Grams](https://tidyunits.com/calculators/cups-to-grams/): Convert US cups to grams for flour, sugar, butter, milk and more. 1 cup of all-purpose flour is about 125 g; 1 cup of sugar is about 200 g. - [Oven Temperature Converter](https://tidyunits.com/calculators/oven-temperature-converter/): Convert oven temperatures between gas mark, °C, °F and fan oven. Gas mark 4 = 180 °C = 350 °F = 160 °C fan. Full chart from ¼ to 9. - [Pace Converter](https://tidyunits.com/calculators/pace-converter/): Convert running pace between min/km and min/mile, and see your speed and finish times for 5K, 10K, half marathon and marathon. - [Time Zone Converter](https://tidyunits.com/calculators/time-zone-converter/): Convert a date and time between time zones, with daylight saving handled automatically. New York, London, India, Sydney and 40+ more cities. - [Unix Timestamp Converter](https://tidyunits.com/calculators/unix-timestamp-converter/): Convert a Unix timestamp (seconds or milliseconds since 1970) to a readable date, in UTC or any time zone. Also shows ISO 8601 and milliseconds. - [Download Time Calculator](https://tidyunits.com/calculators/download-time-calculator/): How long will a download take? Enter the file size and your internet speed. A 50 GB game on a 100 Mbps connection takes about 1 hour 7 minutes. - [Mulch Calculator](https://tidyunits.com/calculators/mulch-calculator/): How much mulch do you need? Enter the bed size and depth to get cubic yards, cubic feet and bags. A 20 × 10 ft bed at 3 in takes 1.85 yd³ (25 bags). - [Topsoil Calculator](https://tidyunits.com/calculators/topsoil-calculator/): How much topsoil do you need? Enter area and depth for cubic yards, cubic meters and bags. A 20 × 10 ft area 4 in deep takes 2.47 yd³ of soil. - [Gravel Calculator](https://tidyunits.com/calculators/gravel-calculator/): How much gravel do you need, in cubic yards and tons? Enter area and depth. A 20 × 10 ft area 3 in deep needs 1.85 yd³, about 2.5 US tons. - [Raised Bed Soil Calculator](https://tidyunits.com/calculators/raised-bed-soil-calculator/): How much soil fills a raised bed? Enter size, depth and number of beds for cubic feet, cubic yards and bags. An 8 × 4 ft bed 12 in deep takes 32 ft³. - [Plant Spacing Calculator](https://tidyunits.com/calculators/plant-spacing-calculator/): How many plants fit in a bed? Enter bed size and spacing for square or staggered rows. A 10 × 4 ft bed at 12 in spacing holds 40 plants (46 staggered). - [Fertilizer Calculator](https://tidyunits.com/calculators/fertilizer-calculator/): How much fertilizer to apply for a nitrogen rate. 1 lb of N per 1,000 sq ft from a 24-0-11 product means 4.17 lb per 1,000 sq ft. US and metric. ## Guides - [DPI vs PPI: which number the printer actually wants](https://tidyunits.com/guides/dpi-vs-ppi/): DPI and PPI explained: why print size is pixels ÷ PPI, why the 72 vs 300 setting changes nothing on screen, and how many pixels a sharp print needs. - [Mbps vs MB/s: why your download is slower than your plan](https://tidyunits.com/guides/mbps-vs-mbs/): Internet plans are sold in megabits, downloads shown in megabytes. Why 100 Mbps tops out near 12 MB/s, and how to estimate real download times. - [px, rem and em in CSS: when to use each](https://tidyunits.com/guides/px-rem-em/): How px, rem and em differ in CSS, why em compounds, what the 62.5% trick costs, and which unit respects the reader's font size setting. - [US vs UK measurements: gallons, pints, cups and tons](https://tidyunits.com/guides/us-vs-uk-measurements/): A UK gallon is 20% bigger than a US gallon, pints and tons differ too, and a UK fluid ounce is smaller. How the two systems split, with exact values. - [Why a 1 TB drive shows 931 GB](https://tidyunits.com/guides/why-1tb-shows-931gb/): Drive makers count in powers of 1,000, Windows in powers of 1,024. Why a 1 TB drive shows as 931 GB, which systems do what, and how to work out the real size. ## About the site - [About TidyUnits](https://tidyunits.com/about/): what the site is, who it is for and how it is funded. - [How we check values](https://tidyunits.com/editorial-policy/): sources, decimal arithmetic, automated tests and corrections. - [Contact](https://tidyunits.com/contact/): report a wrong value or request a tool. ## Optional - [Full text for language models](https://tidyunits.com/llms-full.txt): every tool's formula, key values, answers, common situations and sources, and every guide, in one file. - [Sitemap](https://tidyunits.com/sitemap-index.xml)