How is line-height calculated?

A unitless line-height multiplies the font size to give the line box height. For 16px text with a line-height of 1.5, the line box is 16 × 1.5 = 24px.

Should I use a unitless or pixel line-height?

Unitless values are recommended because child elements inherit the ratio and recompute against their own font size, whereas a fixed pixel value is inherited as-is and can crowd larger nested text.

Is anything uploaded?

No — the calculation runs entirely in your browser and nothing is sent anywhere.

Line Height Calculator

Convert between unitless line-height and pixel line boxes.

CSS line-height calculator

A unitless line-height is a multiplier of the element’s font size: line-height: 1.5 on 16px text produces a 24px line box (16 × 1.5). This calculator converts in both directions — ratio to pixels, or pixels back to the unitless ratio.

Prefer unitless line-heights so nested elements inherit the ratio rather than a fixed pixel height. Enter your values above and both forms update instantly, all in your browser.