Calculating your line height is straightforward once you know the CSS Line Height formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the CSS Line Height Calculator.
What is CSS Line Height?
The CSS Line Height calculation tells you your line height from a few simple inputs. The figure you are solving for here is the line height.
The CSS Line Height formula
The core formula is:
Line height = Font size × Line height ratioHere is what each input means:
- Font size — a value measured in px. Example: 16 px.
- Line height ratio — a number. Example: 1.5.
How to calculate it step by step
- Write down the font size (for example, 16 px).
- Write down the line height ratio (for example, 1.5).
- Apply the formula above to get your line height.
- Double-check the result with the CSS Line Height Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Font size | 16 px |
| Line height ratio | 1.5 |
| Line height | 24.00 |
With font size of 16 px and line height ratio of 1.5, the line height works out to 24.00.
Example 2
With font size of 32 px and line height ratio of 1.5, the line height works out to 48.00.
| Result | Value |
|---|---|
| Line height | 48.00 |
Example 3
With font size of 8 px and line height ratio of 1.5, the line height works out to 12.00.
| Result | Value |
|---|---|
| Line height | 12.00 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the CSS Line Height Calculator does it instantly, for free, with the formula and a worked example built in.
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