macOS
On macOS, Karabiner-Elements is the standard way to remap Caps Lock while keeping the rest of your keyboard behavior predictable.
Step by step
1. Install Karabiner-Elements and finish the permission prompts
Install Karabiner-Elements first, then make sure the background service, Input Monitoring permission, and driver extension are all allowed. These are the required macOS settings.
2. Remap Caps Lock in Simple Modifications
Open Karabiner-Elements, choose Simple Modifications, select the keyboard you want to edit, and change Caps Lock to Left Control. If you prefer Escape instead, you can choose that here too.
3. Optional: make the same mapping work before login
If you want the same mapping on the password screen before login, open the Misc tab in Karabiner Settings and use “Copy the current configuration to the system default configuration.” This makes the same mapping available before logging in.
4. Optional: only continue if Caps Lock is already your language-switch key
The next steps are only for multilingual setups that already depend on Caps Lock for input-source switching. Moving input-source switching to another key lets you keep a separate language-switch key even after remapping Caps Lock, and it can reduce the occasional glitches that come with relying on a short Caps Lock tap to switch modes. If Caps Lock is not doing that job on your Mac, you can stop after the basic remap and skip the rest of this section.
4-1. Pick a spare right-side modifier
Choose a spare right-side modifier for language switching first. A common choice is Right Command -> F18. You can also use Right Option -> F18 instead, as long as that key is not already important in your layout.
4-2. Map that right-side key to F18 in Karabiner
In Simple Modifications, add either Right Command -> F18 or Right Option -> F18, depending on which key you picked in the previous step. This frees Caps Lock for remapping while keeping a dedicated language-switch key on the right side of the keyboard.
4-3. Assign F18 to input-source switching in macOS
Open Apple menu > System Settings > Keyboard > Keyboard Shortcuts > Input Sources, then assign F18 to “Select next source in Input menu.” This recreates a reliable language-switch key after Caps Lock has been repurposed. F18 is used here as a practical example. Because F1 through F12 are tied to built-in system features, a higher-numbered function key is often easier to use for input-source switching. Among them, F18 is one of the keys that is usually safe to use.
Notes
- If you want to verify key names before saving changes, Karabiner’s EventViewer shows what macOS and Karabiner see from each key.
- On macOS, you cannot assign the ⌘ command key to input-source switching.
- If you still need Caps Lock sometimes, keep it on another key you rarely use instead of removing it completely.
References