X-Height & Line-Spacing Calculator
Turn a font size and an x-height ratio into pixel measurements, work out a line height from a leading multiplier, and get a suggested leading for a given line length.
Spacing measurements
Why these numbers matter
Two typefaces set at the same point size rarely look the same size, because their x-heights differ. A typeface with a tall x-height reads larger and can feel more legible at small sizes, while a typeface with a shorter x-height and longer ascenders and descenders often reads as more elegant or classical. Knowing the x-height in actual pixels helps when you're aligning lettering baselines against a grid or comparing two typefaces side by side.
Line spacing works alongside x-height: too tight, and ascenders and descenders from adjacent lines start to collide; too loose, and a paragraph feels disconnected. The leading multiplier this tool uses (line height divided by font size) is the same figure most design software calls "line spacing" or "leading," so the output should map directly onto whatever tool you're setting type in.
Frequently Asked Questions
What is x-height, and why does the ratio change by typeface?
X-height is the height of a typeface's lowercase letters that have no ascender or descender — the letter "x" is the usual reference. It's expressed as a fraction of the font size, and that fraction varies a lot: a typeface like Verdana has a tall x-height (over 0.55) built for screen legibility, while a classic serif like Times New Roman sits closer to 0.45. Two typefaces set at the same point size can look noticeably different in scale because of this.
How is line height different from leading?
Line height is the total vertical space a line of text occupies, and leading is the extra space added on top of the font size to get there — leading = line height minus font size. This calculator asks for a leading multiplier (line height ÷ font size) because that's how CSS line-height and most design tools express it, then reports both numbers in pixels.
Why does longer line length need more leading?
When a line of text runs long, the eye has to travel further to find the start of the next line. Extra vertical space between lines makes that jump easier to make accurately, which is why typographers commonly loosen leading as a text column gets wider. This tool's suggestion is a general guideline based on common practice, not a fixed rule — always check how it actually reads.
Where do I find the x-height ratio for a specific typeface?
Most type specimen pages and some font-inspection tools report x-height as a percentage of the em (font size). If you can't find a published figure, you can measure it yourself: set a lowercase "x" at a known size, measure its height in the same units, and divide.
Educational tool only. Results are exact arithmetic rounded for display, based on the ratio and multiplier you supply — always confirm the look of a specific typeface by eye before finalising a design.