PX to Percent Converter

Express a pixel font size as a percentage of the parent element size.

Pixels
Percent
Runs locally in your browser

About the PX to Percent Converter

Percentage font sizes are measured against the parent element, which makes them a relative unit much like em but written the way many designers already think. This converter turns a pixel target into the percentage that produces it, given whatever parent size you specify.

With a 16px parent, 100% is 16px, 87.5% is 14px and 125% is 20px. Change the parent field to match the real context and the percentages adjust with it, so inside a 14px card a 12px target works out at about 85.71%. Percentages and em describe the same relationship, which is why 1.25em and 125% render identically for font-size.

One practical use is the root reset that many stylesheets still carry: applying html { font-size: 62.5% } makes the root 10px, because 62.5 percent of the 16px default is 10. Percentages also appear on widths and heights, but there they refer to the containing block instead of a font size, so a width figure converts against a completely different reference. The reverse direction lives in Percent to PX.

How to use

  1. Enter the pixel font sizes, one per line.
  2. Set the parent font size in the base field.
  3. Copy the percentage values.
  4. Check the table for the ratios you use most.

Common questions

What percentage is 14px?
87.5% of a 16px parent. Adjust the base field when the parent uses a different size.
Is a percentage the same as an em?
For font-size, yes. A rule of 150% and a rule of 1.5em produce the same result.
Does this work for widths?
No. A percentage width refers to the containing block rather than a font size, so you would need the container width as your base.
Where does 62.5% come from?
It is 10 divided by 16, a common reset that makes the root font size 10px so rem values read easily.