ANSI vs ISO: Which Keyboard Layout Should You Choose?

9/25/2025 · Keyboards · 6 min

TL;DR

ANSI and ISO are the two most common full size keyboard layouts. The choice comes down to key shape, Enter key style, left shift size, and regional availability.
If you care about wide left shift and an easy habit for many US users, pick ANSI.
If you type in European languages, prefer compact Enter and extra key near left shift, or need a layout common in your region, pick ISO.
For custom keycap compatibility and builds, check stabilizer positions and bottom row differences before you buy keycaps.

ANSI stands for American National Standards Institute. It is the dominant layout in the US and many custom keyboards.
ISO stands for International Organization for Standardization. It is common in Europe and some other regions.
The two layouts are identical in most respects but differ at a few key locations that affect typing feel and keycap compatibility.

Enter key: ANSI uses a wide rectangular Enter. ISO uses a tall L shaped Enter. That changes keycap shape and sometimes row profile.
Left shift: ANSI has a long left shift. ISO typically has a shorter left shift plus an extra key between shift and Z.
Backslash/pipe key: ISO often places this key next to left shift or above it; ANSI usually places it above Enter or next to backspace depending on variant.
Bottom row and modifiers: Some keyboards combine both styles or use alternative bottom rows. Custom boards may use nonstandard sizes, so check the exact measurements.

Muscle memory matters: if you learned to type on ANSI, switching to ISO can cause accidental presses around left shift and Enter. Give yourself a few days to adjust.
ISO can feel more ergonomic for some users who like the extra key near left shift for language specific characters.
ANSI is simpler for shortcuts that rely on a wide left shift or when using certain modifier combos.

ISO is more common in many European countries because it accommodates additional characters used in local languages.
ANSI dominates in the US, Canada, and many custom keyboard communities.
If you need quick access to accented characters and your OS keyboard maps match ISO, that may be a reason to choose ISO.

Keycap compatibility: ANSI keycaps are more widely available in some markets. ISO keycap sets exist but often cost more or are region specific.
Stabilizers and plate cuts: Check whether your keyboard plate and PCB support ISO Enter and the extra key near left shift. Not all boards are offered in both variants.
If you plan to buy aftermarket keycaps, confirm the set includes the correct ISO Enter and 1u key for the left shift area.

Choose ANSI if:
You learned to type on US layouts or use many US-centric shortcuts.
You want the widest selection of keycaps and easier compatibility with popular custom sets.
You prefer a wide left shift and rectangular Enter.
Choose ISO if:
You type in languages that benefit from the ISO mapping or you live in a region where ISO is standard.
You like the extra key near left shift or prefer the L shaped Enter.
Your local retailers and replacement keycaps support ISO.

Check the PCB and plate support for ANSI or ISO before buying.
Confirm the keycap set includes an ISO Enter and required 1u key for left shift area.
If buying used, verify the case has the right cutouts and stabilizer compatibility.
Test layout in software if you are unsure: remapping can mimic the other layout while you try it out.

Software remaps can change key functions without moving physical keys. That helps if you want ISO behavior on an ANSI board or vice versa.
Physical keycap and shape differences remain, so remapping does not change where your thumbs or pinky land.

There is no universally better choice. ANSI is best for US users and for the widest hardware and keycap support. ISO is best for European language users and those who prefer the compact Enter and extra key near left shift. For custom builds, confirm compatibility before buying keycaps or plates to avoid surprises.

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