Test every switch on a mechanical keyboard — spot dead keys, chatter and a failing switch before you replace the board.
Simply press any key on your keyboard to test it — if it works it will turn green
0Keys Pressed0Total Keys0%Tested
QWERTY on the US ANSI shape: a wide flat Enter and a full-length left Shift. Standard key positions, with no vendor-specific extras.
Ctrl+W, Ctrl+T, Ctrl+N, Alt+Tab and the Windows or Command key are reserved by the browser and the operating system. No web page receives them, so they cannot be tested here or anywhere else in a browser.
Keys shown greyed out with a dashed outline cannot be tested: your keyboard handles them internally and the browser never receives a key event for them. They are excluded from the totals, so 100% stays reachable.
At a glance
Key counts and layout facts
Detail
Value
Tests for
Dead switches, missing keys, layout mismatches
Also worth checking
Chatter, in a text field
Rollover
See the ghosting test
Form factors covered
Full size, TKL, 75%, 65%, 60%
Switch types
All — the test reads key events, not switches
Hot-swap diagnosis
Move the switch; see if the fault follows
Install required
No
Data sent anywhere
None
A mechanical keyboard in numbers
The board opens on a tenkeyless layout, the most common mechanical size.
87
Testable keysOn the TKL layout this page opens with.
3
Faults a tester findsDead switches, chatter and rollover limits.
50
Million rated pressesThe usual switch rating, and why chatter takes years to appear.
1
Minute per boardFast enough to check a bag of returned stock.
How to test a mechanical keyboard
Mechanical boards fail per switch, so test per switch.
1
Set the layout to match
Pick the form factor and character layout your board uses. A mechanical board can be any size, and testing a 65% against a full size diagram leaves 37 caps permanently blank.
2
Press every key once
Work along each row. Every switch that registers turns green and stays green, so the remaining white caps are your to-do list.
3
Then test for chatter and rollover
Type each suspect key into a text field and count the characters produced. Then hold three, four and five keys together and count how many stay lit.
What to check on a mechanical board
Five checks that only apply to mechanical switches.
Switch chatter
One press producing two characters is debounce failing inside the switch. The cap flickers here rather than holding its colour.
Worn switches under WASD
A gaming board takes far more presses on four keys than anywhere else. Press each of W, A, S and D ten times and count the registrations.
Hot-swap makes diagnosis cheap
On a hot-swap board, move a switch from a key you never use to the failing position. If the fault follows the switch, the switch is the problem.
Rollover and NKRO claims
Hold five keys at once. A board advertised as NKRO that drops the fourth is either running in 6KRO compatibility mode or not delivering the claim.
Stabilised keys
Spacebar, Enter, Backspace and both Shifts ride on stabilisers. Press each at its edges as well as its centre.
Everything about this layout
The shape, the trade-offs and what to watch for when testing it.
01
The three faults worth testing for
A dead switch is the simplest: the key never reports, and it stays dark here no matter how hard you press. Causes range from debris in the housing to a broken solder joint to a genuinely worn-out switch.
Chatter is a switch bouncing — one press producing two or more characters. This test will still light the key green, so chatter is best confirmed in a text field. Type a single press of the suspect key thirty times and count the characters.
Rollover failures show up only when several keys are held at once. A board with limited rollover will silently drop the third or fourth simultaneous key, which matters in games far more than in typing. The ghosting test page covers that specifically.
02
Why hot-swap changes the diagnosis
If your board is hot-swappable, a dead switch is a two-minute repair rather than a soldering job. Pull the keycap, pull the switch with a puller, and drop in a spare.
It also gives you a definitive test. Move the suspect switch to a key position you never use, and move a known-good switch into the failing position. If the fault follows the switch, the switch is bad. If the fault stays with the position, the problem is the socket, the trace or the controller.
That single swap distinguishes a five-pound fix from a board-level repair, and it takes less time than reading about it.
03
Cleaning a mechanical board properly
Pull the keycaps with a wire puller rather than a plastic one, which is far less likely to scratch them. With the caps off, most debris comes out with compressed air aimed across the switches at a shallow angle rather than straight down into them.
For a switch that has taken liquid, isopropyl alcohol of 90% or higher evaporates cleanly and will often revive a contact that sugar has stuck together. Let it dry fully before powering the board back on.
Do not lubricate a switch to fix a fault. Lubricant changes how a switch feels and sounds; it does not repair a broken contact, and applying it to a switch that is already failing usually just makes the failure messier to diagnose.
04
Testing a board you are about to buy
If you are buying used, this page is the fastest possible acceptance test. Load it, select the matching form factor, and press every key. A working board reaches 100%, and anything short of that is a specific key you can point at.
Then check for chatter in a text field, because a board can reach 100% here and still double-type. And check rollover by holding several keys at once if the board will be used for gaming.
Do all three before the return window closes. Dead keys and chatter are both grounds for a return that sellers rarely dispute, but only if you find them early.
Mechanical boards by form factor
Mechanical is a switch type, not a size — pick the size you actually own.
Testable key count and features by layout
Layout
Testable keys
Function row
Arrow keys
Number pad
Full size (100%)
104
Yes
Dedicated
Yes
Tenkeyless (TKL)
87
Yes
Dedicated
No
75% compact
83
Yes
Integrated
No
65% compact
67
No
Integrated
No
60% mini
60
No
Fn layer
No
Switch type does not change the key count. Set the form factor to match your board before reading the score.
Fixing a mechanical keyboard
Four faults and what each one costs to fix.
1One key types twice
On the test:The cap flickers instead of holding its colour.
Type the key once into a text field and count the characters.
Flush the switch with contact cleaner, working the stem 20 times afterwards.
Replace the switch on a hot-swap board, which takes about a minute with a puller.
Raise the debounce time in QMK or VIA if your firmware exposes it.
2A switch feels different from its neighbours
On the test:The key registers, but the press feel is scratchy or inconsistent.
Pull the keycap and compare the stem travel against a neighbouring switch.
Check for debris inside the housing, which is the usual cause of scratchiness.
Swap the switch with a known-good one to confirm before ordering replacements.
3The board drops keys when several are held
On the test:The fourth or fifth simultaneous key never lights.
Hold keys one at a time while keeping the previous ones down, and count where it stops.
Look for an NKRO toggle in the firmware, often Fn plus N on boards that support it.
Try a different USB port. Some hubs and KVM switches force 6-key boot protocol.
Accept 6 keys plus modifiers as normal for any board using the standard USB HID protocol.
4RGB works but a key does not register
On the test:The lighting under a key is fine, the switch sends nothing.
Note that lighting and switch matrix are separate circuits — working RGB proves nothing about the switch.
Swap the switch to a known-good position, on a hot-swap board.
Check the switch pins are straight. A bent pin folded under the housing is the most common hot-swap fault.
Frequently asked questions
How do I know if a mechanical switch is dead?
Press it here. If the key never lights up while its neighbours do, the switch, its solder joint or its socket has failed. On a hot-swap board, move that switch to another position — if the fault follows the switch, the switch is the problem.
What is keyboard chatter and can this test detect it?
Chatter is a bouncing switch sending several presses for one push. This page lights the key green either way, so it will not flag chatter directly. Open a text field, press the suspect key thirty single times, and count whether you get thirty characters.
Does switch type affect the test?
No. The test reads the key events your keyboard sends, which are identical whether the switch underneath is linear, tactile, clicky, optical or Hall effect. What differs between switch types is feel and actuation, not what gets reported.
My RGB lighting keys do nothing here. Is that a fault?
No. Lighting controls, volume wheels and macro keys are handled inside the keyboard firmware and usually send no standard key code at all, so no browser can see them. Test those against their actual function instead.
Can I test a keyboard before buying it used?
Yes, and you should. Select the matching form factor, press every key, and confirm the board reaches 100%. Then check for chatter in a text field and rollover with several keys held at once. All three faults are grounds for a return if you find them early.
Test another keyboard
Every layout below opens with its own board ready to test.
