Start with your work, not a percentage
Write down the keys you use without thinking for a normal week. Include the number pad, function row, arrows, navigation cluster, Delete, Print Screen, and any shortcuts that depend on the right-side modifiers. This list is more useful than asking which size is most popular.
Then separate “must be on the base layer” from “fine behind Fn.” A layer is simply another key map, but every moved key adds a small recall cost. That cost is easy to accept for an occasional media command and harder to accept for a key used hundreds of times a day.
What each common size actually changes
| Size | Usually keeps | Usually moves or removes | Good fit when |
|---|---|---|---|
| Full-size / 100% | Number pad, function row, arrows, navigation keys | Nothing from the standard desktop layout | Numeric entry or one-key access matters more than desk space |
| TKL / 80% | Function row, arrows, navigation cluster | Number pad | You want familiar navigation with more mouse room |
| 75% | Function row and arrows in a compact block | Number pad; some navigation keys may shift | You want compact width without giving up F-keys |
| 65% | Arrows and a small navigation column | Function row and number pad | Arrows matter but F-keys can live on a layer |
| 60% | Main alphanumeric block | Dedicated arrows, F-row, navigation, and number pad | You are comfortable designing and learning layers |
These are families, not strict blueprints. Two 65% boards can place Delete, Page Up, and the right-side modifiers differently. Product photos and the PCB layout diagram outrank the percentage printed in the name.
Size, physical layout, and logical layout are different
- Size describes the rough footprint and which clusters are present.
- Physical layout describes key positions and sizes: ANSI versus ISO Enter, split Backspace, split Shift, a 6.25u or 7u bottom row, and so on.
- Logical layout describes what each key sends. Firmware and your operating system can change this without moving the switches.
This distinction prevents a common expensive mistake: buying a keycap set advertised for “65%” that lacks the exact right Shift or bottom-row keys used by your particular 65% board.
Treat split and ergonomic layouts as a workflow change
Alice-style, column-staggered, ortholinear, and split keyboards can change hand position and key placement substantially. The name alone does not guarantee a specific geometry. Check the actual plate drawing, thumb cluster, tenting options, and firmware before ordering.
Plan for an adjustment period and keep a known keyboard available for urgent work. A layout can be thoughtfully designed and still be wrong for your shortcuts, mobility needs, or shared desk.
Make the decision in fifteen minutes
- Circle every dedicated key you use at least weekly.
- Choose the smallest family that keeps the non-negotiable clusters.
- Open the exact product layout diagram and check every non-standard key.
- Confirm that its firmware can put missing keys where you want them.
- Check the matching keycap sizes before committing to the kit. The keycap guide shows what to verify.
Sources and further reading
- LayersQMK Firmware
How layered keymaps resolve key presses.
- Keyboard definition specificationVIA
How physical layouts and configurable elements are represented.