Keyboard size labels describe the approximate arrangement of keys, not a universal mechanical standard. They are helpful for recognizing a board at a glance, but they do not tell you every key size you need for a replacement keycap set.
60%
A typical 60% board keeps the main typing area and removes the function row, navigation cluster, and number pad. Some models use a standard bottom row; others do not.
65%
A 65% board usually adds arrow keys and a small column of navigation keys to a 60% layout. The right Shift and nearby modifiers are common compatibility checkpoints because their sizes vary between designs.
75%
A 75% layout generally adds a function row while keeping the board compact. Key spacing and the right-side navigation column can differ substantially from one model to another.
TKL or 80%
Tenkeyless boards retain the function row, arrows, and navigation cluster but omit the number pad. Many resemble the left portion of a full-size board, though you should still verify the bottom row and spacebar.
96%, 98%, and compact full-size
These layouts fit most or all full-size functions into a tighter footprint. Their compressed navigation area, zero key, and right-side modifiers often use model-specific arrangements.
Full-size
A full-size board normally includes the typing area, function row, navigation cluster, arrows, and number pad. “Full-size” still does not guarantee that every stabilizer and bottom-row key matches a particular set.
Use form factor as the starting point, then check the switch stem, 6.25U or 7U spacebar, stabilized keys, and full included-key layout. See the Keycap Compatibility Guide for a step-by-step check.