Keyboard & Keycap Compatibility

SIMPOCUBIC ISO and ANSI keycap sets fit most mechanical keyboards with standard-height MX-style switches. Extra keys cover common full-size and compact layouts, with a choice of language legends.

1. Check the switch stem

The keycaps attach to the cross-shaped MX-style stem found on many standard-height mechanical switches. Low-profile, laptop, membrane and scissor-switch keyboards need keycaps designed for their mounting system.

MX-style cross stems

Four switch stems: red without a wall, blue with a square wall, pink with a round wall and yellow with an open wall.
  • Red: no outer wall
  • Blue: square wall
  • Pink: round wall
  • Yellow: open wall
Structural illustrations: the central cross is separate from the outer wall. Enlarge image

2. Identify ANSI or ISO

ANSI usually has a wide horizontal Enter key. ISO usually has a tall Enter key and a shorter left Shift. Language legends such as AZERTY or QWERTZ are separate from these physical key shapes.

ANSI and ISO at a glance

ANSI

Horizontal Enter

Enter

Long left Shift

Shift

ISO

Tall Enter

Enter

Short left Shift + extra key

Shift
SIMPOCUBIC multilingual keycap sets support both ANSI and ISO layouts.

3. The bottom row and spacebar

Our ISO and ANSI sets include 1u and 1.25u keys for different positions along the bottom row. Even two ANSI keyboards can use different key widths to the right of the spacebar: the extra keys cover these common variations.

The bottom row, key by key

Example: Keychron V1 ANSI / ISO

A1u1u is a unit of key width: the width of a letter key, not its height.
CtrlAltWinSpacebar6.25uWinFnCtrl
3 × 1.25u6.25u3 × 1u
Three keys on the left
1.25u × 3
Spacebar
6.25u
Three keys on the right
1u × 3
Even in ANSI, key widths can vary with keyboard size. Main block shown without arrow keys; simplified Windows key names. Manufacturer dimensions

4. Keys for compact keyboards

Our sets also include several Shift key widths for common full-size and compact layouts. The diagram shows the difference between a 2.75u and a 1.75u right Shift, and between 1.25u and 1u small keys.

Key sizes for common layouts

Keychron V6 ANSI · full-size

Right Shift

Shift2.75u

Keys to the right of the spacebar

WinAltFnCtrl
4 × 1.25u

Keychron V1 ANSI / ISO · compact

Right Shift

Shift1.75u

Keys to the right of the spacebar

WinFnCtrl
3 × 1u
Our ISO and ANSI sets include extra 1u and 1.25u keys and several Shift widths for these common configurations. Manufacturer dimensions: V6 ANSI · V1 ANSI / ISO

5. Unsure? See the set’s key layout diagram

The diagram on the product page shows the included keys and their sizes.

Common mechanical keyboards

Standard-height MX-style mechanical models from Keychron, Wooting, Akko, MonsGeek, Royal Kludge and EPOMAKER are among the common configurations our ISO and ANSI sets are designed for. Low-profile models and special mounting systems are separate cases.

For more ANSI and ISO comparisons, read our guide.