Kerning is the adjustment of space between two specific characters so that the gap between them looks visually equal to the gaps elsewhere in a word. In typography, it corrects pairs such as AV, To, Ty and LT, whose shapes leave awkward holes or collisions when they are set with their default spacing.
Kerning is usually built into a font by its designer as a list of kerning pairs, and layout software applies it automatically. Designers also kern manually in logos, headlines and other display typography, where large sizes make every spacing irregularity visible.
How kerning corrects letter spacing
Kerning works by adding or subtracting a fixed amount of space between two particular glyphs, on top of the spacing each glyph already carries. Every glyph in a font has side bearings, the built-in space to its left and right, which are set so that most combinations look even.
Some shapes cannot be spaced well by side bearings alone. A capital T has a wide horizontal bar that overhangs empty space, so a following o appears too far away; an A next to a V leaves a large triangular gap. Kerning tightens or loosens just those pairs, aiming for even optical rhythm rather than equal measured distances.
Kerning values are stored in font units, commonly on a grid of 1,000 or 2,048 units per em. Because the values scale with the type size, a kern of -80 units in a 1,000-unit font equals 0.08 em, which is 0.8 pt at 10 pt and 5.76 pt at 72 pt.
The table shows typical problem pairs and the direction of their correction.
| Pair | Spacing problem | Typical correction |
|---|---|---|
| AV, AW, VA | Diagonals create a large gap | Strong negative kern |
| To, Te, Ty | Crossbar overhangs open space | Negative kern under the bar |
| LT, LY | Open space after the L | Negative kern |
| P. and F, | Punctuation sits far from the letter | Negative kern |
| f) and f? | Overhanging f collides with the next glyph | Positive kern |
Kerning compared with tracking and other spacing
Kerning is often confused with tracking, but the two solve different problems. Kerning adjusts one specific pair, while tracking adds or removes the same amount of space across a whole range of text.
| Control | Scope | Main purpose |
|---|---|---|
| Side bearings | Each glyph, set by the type designer | Default spacing of the font |
| Kerning | Specific pairs of glyphs | Correcting awkward combinations |
| Tracking | A word, line or paragraph | Overall looseness or tightness |
| Word spacing | Spaces between words | Line texture and justification |
| Leading | Distance between lines | Vertical rhythm and readability |
The usual order of work is tracking first, kerning second. If a headline is tracked tighter after it has been kerned by hand, the manual corrections can become too strong, because some gaps shrink more noticeably than others.
Methods of kerning
Kerning can be applied by the font’s own data, by software analysis or by hand. Each method suits different situations, and professional work often combines them.
| Method | How it works | Best suited for |
|---|---|---|
| Metric kerning | Uses pairs stored in the font | Body text in well-made fonts |
| Optical kerning | Software calculates spacing from glyph shapes | Fonts with poor or missing kerning |
| Manual kerning | Designer adjusts individual pairs | Logos, headlines and wordmarks |
| Class-based kerning | Pairs defined for groups of similar glyphs | Font development with large character sets |
In modern OpenType fonts, kerning data lives in the GPOS table and is applied through the kern feature, while older fonts may use a legacy kern table. Class-based kerning lets a type designer kern all variants of a letter, such as A, Á and Ä, with one rule, and add exceptions where accents would collide.
On the web, browsers apply font kerning by default in most situations, and the CSS property font-kerning can explicitly enable or disable it. The CSS property letter-spacing controls tracking, not kerning, which is a common source of confusion.
Practical guidelines for kerning
Good kerning aims for even texture, so that no pair attracts attention. Most text never needs manual intervention, but larger sizes reveal problems that are invisible in a paragraph.
- Trust metric kerning for body text in quality fonts; manual adjustment at 10 pt is rarely visible.
- Kern manually at display sizes, typically above about 24 pt, and always in logos.
- Judge spacing visually, not by numbers; one useful method is to view the word upside down so letter shapes are not read as words.
- Check all-caps settings carefully, since capitals produce many diagonal and open combinations.
- Re-check kerning after changing the typeface, because values belong to a specific font and do not transfer.
Very tight display settings can make letters touch or create unintended combinations, such as r and n reading as m. A designer should therefore check headlines at their final size and in their final medium.
Common kerning problems
Kerning problems usually appear as holes, collisions or inconsistent rhythm within a word. The table pairs frequent symptoms with their causes and fixes.
| Symptom | Likely cause | Fix |
|---|---|---|
| Gap in a headline word | Font lacks a needed pair | Add manual kerning |
| Letters colliding | Excessive negative tracking or kerning | Loosen tracking first |
| Uneven logo spacing | Metric kerning used at large size | Kern each pair by eye |
| Different spacing across apps | Kerning disabled in one environment | Enable font kerning consistently |
In plain words
Kerning is fine-tuning the space between two particular letters. Some letters fit together naturally, while others, like a capital A next to a V, leave a gap that makes a word look as if it has a hole in it.
Kerning nudges those letters closer or further apart so the word looks evenly spaced. When it is done well, nobody notices it, and the text simply looks tidy.
A real-world example
A designer prepares a wordmark for a travel agency named VOYAGE AWAY, set in a geometric sans serif at about 120 pt. With default metric kerning, the pairs VO, YA, AW and WA leave visible wedges of white space, so the word looks broken into pieces.
The designer first sets slightly loose tracking suitable for capitals, then kerns each pair by eye, tightening VO and AW by roughly 40 to 70 font units and leaving straighter pairs nearly unchanged. The design is checked at small sizes and printed at full size.
The final wordmark reads as one confident unit, and the spacing remains balanced when the logo is reproduced on signage and business cards.