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Gallons to Liters

Gallons (US) (gal) to liters (L).

Result18.9271L

Precision (significant figures)

Formula

L = gal × 3.78541

1 gal = 3.78541 L

liters = US gallons × 3.785411784 exactly. So 5 gallons is 18.9271 L and 55 gallons (a drum) is 208.198 L. If the gallons are imperial (UK), multiply by 4.54609 instead: 5 UK gallons is 22.7305 L.

Formula

L = gal × 3.78541

Worked example

  1. Start with 5 gal.
  2. Multiply by 3.78541 (L per gal): 5 × 3.78541 = 18.9271 L.

Gallons to liters chart

Gallons (US) (gal)Liters (L)
0.250.946353
0.51.89271
13.78541
27.57082
311.3562
518.9271
1037.8541
1245.4249
1556.7812
2075.7082
2594.6353
50189.271
55208.198
100378.541
5001,892.71
1,0003,785.41

When you need this conversion

Reading US recipes, fuel figures, water heater and aquarium sizes, paint coverage, and chemical dosing instructions in a metric country.

Quick reference (US gallons)

  • 1 gal = 3.78541 L
  • 2 gal = 7.57082 L
  • 5 gal = 18.9271 L
  • 10 gal = 37.8541 L
  • 50 gal = 189.271 L

Where the numbers come from

The US gallon is defined as 231 cubic inches. With the inch at exactly 2.54 cm, that’s 3,785.411784 cm³, or 3.785411784 L, exactly. The UK gallon is defined directly as 4.54609 L.

Common mistakes

Mixing US and UK gallons. A British recipe or car manual using gallons means imperial gallons.

Rounding to 4 L per gallon. It’s 5.7% high; on a 20-gallon tank, that overstates the volume by 4.3 L.

For the reverse, use liters to gallons.

Questions

How many liters is 1 gallon?

3.78541 L for a US gallon; 4.54609 L for a UK gallon.

How many liters is 5 gallons?

18.9271 L (US), or 22.7305 L (UK).

How many liters is a 55-gallon drum?

208.198 L.

How many liters of water weigh a gallon?

A US gallon of water holds 3.785 L and weighs about 3.78 kg (8.34 lb).

Sources

Last reviewed 2026-09-24. How we check values · Report a problem with this page

Further reading