Keycap Compatibility Guide
Enter your layout and the non-standard keys your board uses, then see which kit coverage you need and where a base set will leave gaps.
Tool Operation Area
Kit requirements
A standard ANSI base kit should cover this board. Still check the vendor's kitting sheet against your bottom row before ordering.
All MX-compatible caps share the same cross stem, so fit is never the problem — layout widths are. Verify against the kitting image, not the render.
Working Principle
Keycap sets are sold as base kits sized for a standard ANSI or ISO layout, plus optional extension kits. Compatibility failures almost never involve the alphanumeric block; they involve the bottom row, the modifier widths and the enter key. The standard ANSI bottom row uses 1.25u modifiers with a 6.25u spacebar, and any set with a base kit covers it. Boards that use a 7u spacebar, a 1.5u or 1u modifier row, split backspace, split left shift or split right shift need extra caps that only some kits include. ISO layouts add a further complication because the ISO enter key is a tall stepped shape and the left shift is shorter, so an ANSI base kit cannot serve an ISO board without an ISO kit. Small layouts introduce their own needs: 40% boards require 1u or 2u modifier variants that are rarely in a base kit, and boards with a rotary encoder or an extra column need a spare 1u. The other axis is profile and stem. All MX-compatible caps use a cross stem, so they physically fit any MX switch, but sculpted profiles are row-specific and installing a row 3 cap in row 1 produces an uneven surface. This tool checks the layout side of the problem and lists which named kits, in the conventional naming used by vendors, cover the keys you flagged.
How to Use
- 01Select your layout family.
- 02Tick every non-standard key your board actually uses: 7u spacebar, split backspace, split shifts, stepped caps lock, ISO enter and so on.
- 03Choose whether your board has extra encoder or macro keys.
- 04Read the required kit list, the count of caps you need beyond the base and the risk notes.
- 05Common mistake: buying a set based on a render. Check the kit's own kitting sheet against this list before ordering.
FAQ
Will any MX keycap fit any MX switch?
Physically yes, because the cross stem is standard. Fit issues come from layout widths and from thick-walled caps interfering with tall switch housings.
Can I mix profiles on one board?
Uniform profiles mix reasonably well; mixing sculpted rows or mixing SA with Cherry produces a very uneven surface.
What is a stepped caps lock?
A caps lock cap with a raised step on the right portion, used on some vintage-inspired layouts. It requires a specific cap that base kits often omit.
Does keycap material affect compatibility?
Not fit, but thick PBT caps sometimes rub against tall switch housings or LED lenses; check clearance if you use shine-through housings.
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