When you need this conversion
Picas measure the page (column widths, margins, gutters) while points measure type and rules. Converting lets you check that a 3p6 gutter really is 42 points, or that a 30-pica column holds lines of 9 or 10 pt type comfortably.
The pica system
- 1 pica = 12 points
- 6 picas = 72 points = 1 inch
- 1 point = 1/72 inch
The modern (DTP or PostScript) pica is exactly 1/6 inch. Older traditional picas were very slightly smaller, but every current application uses the digital definition.
Reading InDesign measurements
InDesign’s 3p6 notation means 3 picas and 6 points: 3 × 12 + 6 = 42 points. A value like 0p9 is 9 points. You can type either form into any field, and InDesign converts to the current ruler unit.
Common mistakes
Mixing picas with the CSS pc unit. They’re the same size: CSS defines 1pc as 12pt, or 1/6 in.
Rounding column widths. A 13.5-pica column is 162 points, not 160. Small errors add up across a spread with several columns.
Need inches? Use picas to inches.