What does this tool do?
The Line Height Calculator computes CSS line-height in both pixels and unitless form from a font size and a ratio, with a live preview. It lets you dial in the line spacing that drives readability without trial-and-error guessing. It is a practical tool for designers and frontend developers tuning typography with precision.
How to use it
- Adjust the values and options.
- See the result in the live preview.
- Copy the generated CSS/code into your project.
How it works
The tool multiplies your font size by the ratio you choose to find the line height in pixels, and returns the same ratio as a unitless line-height value. For example, a 16px font with a 1.5 ratio gives a 24px line height. The live preview instantly shows how your chosen value looks on real text.
Common use cases
Use it to set comfortable, readable spacing for body text (typically 1.4–1.6), pick a tighter ratio for headings, and establish consistent vertical rhythm across a design system. The unitless value is especially recommended because it keeps spacing proportional when child elements change font size.
Frequently asked questions
Why is unitless line-height preferred over a px value?
A unitless value computes a proportional line height relative to each element's own font size, so spacing does not break in nested elements. A fixed px value can cram small text or leave large text too airy.
What is the ideal ratio for body text?
Most body text reads comfortably at a ratio between 1.4 and 1.6. Headings often work better with a tighter 1.1–1.3, while small captions can benefit from a slightly looser ratio.
Is Line Height Calculator free?
Yes. Line Height Calculator and all 300+ tools on MagmaNex are completely free with no signup or account required.
Is my data safe?
Yes. Everything runs locally in your browser. The data you enter is never sent to a server, stored, or shared.
Does it work on mobile?
Yes. Line Height Calculator works on phones, tablets and desktops — no app download needed.
🔒 Privacy: everything runs in your browser, your data is never sent to a server.