How to fix keyboard chatter (keys that type twice)

Test it first

Before you take anything apart, make sure the problem is the key and not a setting. The keyboard test times every press to the millisecond and marks a key red when it registers a second press too soon after you let go.

1. Open the keyboard test and pick your keyboard's layout.
2. Press the key that types twice about 20 times, at your normal pace.
3. Look for a red key with a count on it, and for "down (chatter)" lines in the key log.
4. If nothing turns red, raise the chatter threshold to 50 ms and press the key slowly a few more times.
5. Note every key that turns red, then press Finish and get report and copy the report. You'll want it for a warranty claim.

If the test shows no chatter but your documents still get double letters, check the settings in the next section first.

What keyboard chatter is

Most keyboards register a key press when two metal contacts inside the switch touch. The contacts don't meet cleanly: for a few thousandths of a second they bounce, touching and parting several times. The keyboard's firmware waits out that bounce before it reports the press. This wait is called debounce.

When a switch wears, or dust and oxidation build up on its contacts, the bounce lasts longer than the debounce time. The keyboard then reports the bounce as a second press, and you get "thhe" instead of "the". It usually starts with one or two keys you use the most, such as E, Space or the keys you use in games, and gets worse over time.

Chatter is different from key repeat. Repeat is your system typing a key again and again while you hold it down. Chatter happens on a short, single press.

Rule out the settings

A key that seems to type twice isn't always chatter. Check these first, as they take a minute and need no tools.

Key repeat delay

If the delay before repeat is very short, holding a key a little too long types it twice. On Windows 11, open Control Panel → Keyboard and move Repeat delay toward Long. On a Mac, open System Settings → Keyboard and move Delay until repeat toward Long.

Wireless connection

A weak battery or a receiver far from the keyboard can drop the release of a key, which looks like a repeated or stuck key. Charge the keyboard, move the receiver closer, and test again with a cable if your keyboard has one.

Another computer

Plug the keyboard into another computer and run the test there. If the chatter follows the keyboard, the fault is in the keyboard. If it stays behind, look at the first computer's keyboard software and drivers instead.

Clean the switch

Dust, crumbs and dried spills are a common cause of chatter, and cleaning is free. Unplug the keyboard or turn it off before you start.

Mechanical keyboards

1. Pull the keycap straight up with a keycap puller.
2. Hold a can of compressed air upright and blow short bursts into the switch from a few angles.
3. Press the switch quickly a few dozen times to work loose any dirt inside.
4. If that doesn't help, put one drop of electrical contact cleaner into the gap around the switch's stem. Use a cleaner that says it leaves no residue and is safe on plastics, not a general-purpose lubricant spray.
5. Press the switch a few dozen more times, then let the keyboard dry for as long as the cleaner's label says before you plug it back in.
6. Put the keycap back and run the keyboard test again.

Laptop and low-profile keyboards

Laptop keycaps clip onto thin plastic hinges that break easily, so don't pull them off unless the maker's instructions show how. Tilt the laptop on its side and blow compressed air under the key from several directions instead. Don't use liquids on a laptop keyboard.

Raise the debounce time

A longer debounce time makes the keyboard wait longer before it accepts another press of the same key. It hides mild chatter well, and the cost is small: a few extra milliseconds on each press.

In your keyboard's app

Many gaming and enthusiast keyboards come with an app that has a setting called debounce, debounce time or key response. Open your keyboard maker's app, look in the keyboard's performance or advanced settings, and raise the value a few milliseconds at a time until the test shows no chatter.

Keyboards with QMK firmware

QMK sets debounce when the firmware is built, with the DEBOUNCE value in the keyboard's config.h file. The default is 5 ms. Raise it a little, for example to 10 ms, build the firmware and flash it to the keyboard. If your keyboard uses VIA or Vial, check its settings for a debounce option first, or ask the maker for a firmware build with a higher value.

Software on Windows

If your keyboard has no setting, small open-source programs for Windows, such as Keyboard Chattering Fix, ignore a second press of a key that arrives too soon after the first. They run in the background and need to start with Windows. Download them only from the project's own page, and check that the project is still maintained.

Update the firmware

Makers sometimes change the debounce time or fix chatter in a firmware update. Open your keyboard maker's app or support page, look for your exact model, and install any update it lists. Keep the keyboard plugged in by cable while it updates.

Use Filter keys or Slow Keys as a stopgap

Your system can ignore repeated presses for every key. It's a blunt fix that also slows down fast typing, so turn it off once the keyboard is repaired.

Windows 11

1. Open Settings → Accessibility → Keyboard.
2. Turn on Filter keys, then open its options.
3. Turn on Ignore unintended keystrokes and choose the shortest wait time that stops the double letters.

macOS

1. Open System Settings → Accessibility → Keyboard.
2. Turn on Slow Keys. Each key must then be held for a moment before it counts, which also ignores the very short presses that chatter makes.

Replace the switch or use the warranty

If cleaning and debounce don't help, the switch is worn and needs replacing.

• Hot-swappable keyboards let you pull a switch out with a switch puller and press in a new one of the same type, with no soldering.
• Soldered switches need desoldering and soldering a new one in. A repair shop can do it, and it usually ends the warranty.
• Optical and Hall effect switches detect a press with light or magnets instead of touching metal contacts, so they don't chatter the same way. They are worth considering if you replace the keyboard.

Chatter is a hardware fault, so a keyboard under warranty is often repaired or replaced. Check the maker's warranty terms and your retailer's return policy, and attach the report from the keyboard test to your claim. Don't open the keyboard first if you plan to claim: opening it can end the warranty.

Still typing twice?

Run the keyboard test again after each fix, so you know which one worked. If the chatter is still there after cleaning, a higher debounce time and a firmware update, the switch is worn out: replace it, or use the warranty while you can.