Convert picas to pixels at any DPI

A pica turns into pixels in one step: divide the measurement by six and multiply by the DPI. At 96 DPI a pica is exactly 16 pixels, at 150 DPI it is 25 pixels, and at the 300 DPI used for print it is 50 pixels. The figure of 96 pixels per inch comes from the CSS specification.[1]

The six in the formula is there because a pica is exactly one sixth of an inch. Every standard density divides by six with nothing left over, so the answer comes out whole at 72, 96, 150, 300 and 600 DPI.

Column widths, gutters and margins in newspaper and magazine layout are still specified in picas, and those numbers now have to travel into files measured in pixels.

Below you will find a table of 19 measurements at four densities, a comparison of the three pica systems, how to read the 5p6 notation, and what the selector under the fields does. The opposite direction is handled by the pixels to picas converter.

The formula has two steps: pixels = picas ÷ 6 × DPI. The first turns picas into inches, the second turns inches into pixels.

Take a 20-pica column at 300 DPI: 20 ÷ 6 gives 3.333 inches, and 3.333 × 300 gives 1,000 pixels. The same column on screen at 96 DPI is 320 pixels wide.

Screen work has a shortcut: a pica is 16 pixels, which is also the browser’s default text size. The rem to px converter describes that same size, so with default settings 1 pica, 1 rem and 16 pixels cover the same distance.

A pica holds twelve points, and a point is 1/72 of an inch.[2] That gives you the second shortcut: divide a measurement in points by twelve and you have picas. Points on their own are handled by the points to pixels converter, which also lists the menu paths for changing units in design software.

When the spec arrives in inches or in metric units, the same arithmetic is done by the inches to pixels converter, the millimeters to pixels converter and the centimeters to pixels converter.

The unit called a pica has three values today, and all three are still in use. The Pica type selector under both columns switches the arithmetic to whichever one you need.

The PostScript pica is one sixth of an inch, or 4.2333 mm. This is what InDesign, QuarkXPress and the CSS pc unit mean,[1] so it fits anything produced in digital typesetting. It is selected by default.

The printer’s pica measures 400/2409 of an inch, or 4.2175 mm. The United States Type Founders’ Association set that standard in 1886, and TeX and LaTeX still compute with it.[2] Pick it when the measurement comes out of academic typesetting.

The cicero is twelve Didot points, or 4.5128 mm, and it is the unit continental European printing was built on.[3] It is 6.6% wider than a PostScript pica, so at 300 DPI it comes to 53.30 pixels against 50. You will meet it in files and specifications coming from Europe.

This converter computes with the Didot point as 0.376065 mm, which makes a cicero 4.5128 mm. Two further definitions are in use alongside it: the original one, built on 1/72 of the French inch, gives 4.5117 mm, and the Polish norm of 2,660 points to the metre gives 4.5113 mm. The extremes are 0.033% apart, so it takes 57 ciceros in a row before the difference reaches a single pixel at 300 DPI.

Publishing software writes a compound measurement: the number of picas, the letter p, then the number of points. 5p6 means five picas and six points, and both InDesign and QuarkXPress use it.[2]

To put that in the converter field, divide the points by twelve and add them to the picas. Six points is half a pica, so 5p6 goes in as 5.5. The field takes a comma as well as a period, so 5.5 and 5,5 both work.

The table below sets out eleven measurements in that notation with their decimal value and their pixel count at 300 DPI. Writing a result back in the same form is covered by the pixels to picas converter.