---
name: Kerning
slug: kerning
category: typography
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-21T00:00:00.000Z
definition: The adjustment of space between two particular letters so the pair
  reads evenly.
aliases:
  - name: kern
  - name: kern pair
  - name: metric kerning
tags:
  - fonts
  - spacing
relations:
  contrastWith:
    - leading
    - tracking
    - optical-kerning
    - word-spacing
    - ligature
  variantOf: []
  partOf: []
  seeAlso: []
implementations: []
sources:
  - title: Kerning (Practical Typography)
    url: https://practicaltypography.com/kerning.html
  - title: "MDN: font-kerning"
    url: https://developer.mozilla.org/en-US/docs/Web/CSS/font-kerning
demo: inline
exhibit: false
useWhen: the space between two particular letters
---

Kerning is a pair operation. It names two letters and moves them closer together
or further apart, because the shapes they were drawn with leave a hole or a
collision when they meet. [Tracking](/tracking) is the other half of the pair
readers mix up, and the difference is the scope: tracking adds one uniform amount
to every letter in a run, while kerning is a value that applies to T next to o and
to nothing else on the line. You kern a pair; you track a line.

Most kerning is already done. The type designer walks the awkward combinations and
writes a correction for each into the font's kern table, which the shaping engine
applies whenever those two letters turn up together, so the word "To" in a
well-made face is already tightened before anyone looks at it. The pairs anyone
notices are the diagonal or open shape against the round or narrow one: T over o,
V beside a, Y before e, W against a comma, and capitals standing next to lowercase
generally. A table typically holds a few hundred of them. What is left over is the
hand kerning a designer does at poster sizes, one pair at a time, where a table
tuned for text cannot know how the line will be used.

On the web the table is the whole story. `font-kerning: normal` asks for it,
`none` switches it off, and `auto` leaves the decision to the browser, which in
practice means on for the text sizes that matter. Two things quietly remove it.
Shaping stops at element boundaries, so wrapping one letter of a pair in its own
span to colour it also throws away the pair's kern, and a
[font subset](/font-subsetting) that drops the `kern` and `GPOS` data ships a
face whose corrections are simply gone. Neither failure announces itself: the line just
looks slightly lumpy at display size.

What no browser offers is the third way. [Optical kerning](/optical-kerning)
computes the space from the outlines rather than reading it from the table, and
since no engine implements it, web typography is the font's pairs or nothing. That
puts the weight back on the face: at 16px a poor pair costs almost nothing, and at
72px it is the first thing a reader sees, which is why display type is where both
the font choice and the correction are worth the attention. Body text is better
served by getting the [leading](/leading) right.