Find the cause step by step
- USB keyboard on Android: plug an OTG adapter into the phone and the keyboard into the adapter. Many keyboards light up when they get power.
- Bluetooth keyboard: put the keyboard in pairing mode and choose it under Bluetooth on the phone.
- iPhone: models with USB-C take a USB keyboard through a USB-C adapter; Lightning models need Apple’s Lightning to USB (camera) adapter.
- Open this page on the phone, tap the box above and press the keys one by one. The ones that work show up in the list.
- Some keys never show up on any website: Fn, and media or macro keys handled by the keyboard itself. That’s not a fault.
Symptom, cause and fix
| Symptom | Likely cause | What to do |
|---|---|---|
| USB keyboard | OTG adapter on an Android phone | Open this page and press the keys |
| Bluetooth keyboard | Pair it with the phone | Same test in the box above |
| iPhone with USB-C | USB-C to USB adapter | Same test |
| Keyboard doesn’t light up or show up | Phone without OTG or not enough power | Test on another phone or a PC |
Related questions
Does every phone accept a USB keyboard?
Most Android phones with USB-C do. If nothing happens, the phone may lack OTG or not supply enough power, for example for keyboards with lots of RGB lighting.
Can I test a laptop’s keyboard this way?
No, it’s built in. For a laptop keyboard, test it in the BIOS at startup or see our page on a laptop keyboard not working.
The Fn key doesn’t show up. Is it broken?
No. Fn is handled inside the keyboard and no website can detect it. Test combinations with it, like Fn + a volume key.
How do I test a keyboard PCB without a computer?
You still need something to power it and read the keys: plug the bare PCB into a phone with OTG, open this page and bridge each switch’s two pads with tweezers. Every key that shows up is working.
More problems: keyboard test
- A key on your laptop not working: how to test and fix it
- Laptop keyboard not working: what to do first
- Keyboard typing by itself: how to fix it
- Keyboard typing numbers instead of letters: how to fix it
- Keyboard typing wrong characters: @ and " swapped, # turned into £
- Keyboard typing double letters: how to fix it
- Keyboard locked: how to unlock it
- Mechanical keyboard key not working: how to fix it
- USB keyboard not working on your PC: how to fix it
- How to test a keyboard: online, mechanical, wireless, MacBook and BIOS
Updated November 12, 2026.