Tracking vs. Kerning: What's the Difference?

Tracking and kerning get used almost interchangeably in casual conversation, but they're doing genuinely different jobs, and mixing them up is a common source of confusion when you're trying to fix spacing that looks off. The short version: kerning is about specific letter pairs, and tracking is about a whole range of text at once.

Kerning: fixing individual pairs

Kerning adjusts the space between one specific pair of letters. Some letter combinations, if spaced with a uniform gap, look like they have too much air between them — a capital "A" next to a capital "V" is the classic example, since the diagonal strokes lean away from each other and leave a visual gap wider than the space next to two straight-sided letters. Kerning pulls that specific pair closer together (or, less often, pushes a pair apart) to even out the visual rhythm.

Most typefaces ship with a kerning table built in — a list of problem pairs and how much to adjust each one — so kerning often happens automatically the moment you type. Manual kerning comes in when you're setting a headline or logotype at large size, where every letter pair is magnified enough that even small spacing irregularities the built-in table didn't anticipate become visible, and a designer adjusts pairs by eye.

Tracking: adjusting a whole range uniformly

Tracking, by contrast, applies one uniform adjustment across an entire selection of text — a word, a line, a whole paragraph. It doesn't care which specific letters are next to each other; it just adds or removes the same amount of space everywhere. You'd use tracking to loosen up a line of small caps so the letters don't feel like they're crowding together, or to tighten a large display headline so its letters don't look like they're floating apart.

Because tracking is uniform, it's the tool for a whole-block decision — "this heading needs to feel more open" or "this line needs to feel tighter" — while kerning is the tool for a local, pair-by-pair correction once the overall tracking is already set the way you want it.

Different units, same underlying idea

Both tracking and kerning are ultimately expressed as a fraction of the em (the font size), but different software displays that fraction differently. CSS's letter-spacing property takes a raw em or pixel value. Page-layout tools like Adobe InDesign and Illustrator historically use thousandths of an em for tracking, so a value of "20" means an extra 0.02em between each character. Some interfaces just show a plain percentage. None of these are actually different concepts — they're the same fraction-of-the-em idea, expressed in different units for historical and interface reasons.

A size-dependent rule of thumb

One widely used guideline is that tracking should move in the opposite direction from font size: the bigger the type, the tighter (more negative) the tracking should be, and the smaller the type, the more positive tracking helps. This is because the same absolute gap between letters looks proportionally larger at bigger sizes — a gap that reads as comfortable at 12 points can look loose and disconnected once the same letters are blown up to 72 points for a poster headline. All-caps settings are a related special case: because capital letters lose the varied silhouette that lowercase ascenders and descenders provide, a touch of extra tracking often helps keep individual words from reading as one dense, undifferentiated block.

Putting the two together

In a typical workflow, you'd set the tracking for a whole heading or paragraph first, getting the overall density right, and then zoom in and kern individual pairs that still look off once the general spacing is settled. Doing it in the other order — kerning pair by pair before you've settled on an overall tracking value — usually means redoing the kerning once the tracking changes, since a kerning adjustment made at one tracking value may no longer be the right amount once the surrounding letters have moved.