Keyboard Latency Guides & Technical Explainers

Start here if your keyboard feels slow

Most people arrive with a feeling rather than a number. This five-step path turns the feeling into something you can act on, and it takes about ten minutes.

Measure first. Run the browser-based keyboard latency test and collect at least 30 presses. Fewer than that and the percentiles are noise.
Learn what the number means. Read what counts as a good keyboard latency before comparing your median with anyone else's — the figure depends heavily on your browser, your machine and what else it was doing.
Look at consistency, not just the median. A stable 12 ms feels better than a result that swings between 3 ms and 40 ms. The combined performance test reports spread alongside the average, and why results vary between systems explains what causes the swings.
Rule out duplicate events. A key that occasionally registers twice reads as "unreliable" rather than "slow". The chatter test flags suspiciously fast repeat events, and what keyboard chatter is explains the switch behaviour behind them.
Then change something. How to reduce keyboard input lag separates the changes that measurably help from the advice that does nothing — and tells you how to re-measure so you can prove it either way.

If the problem is intermittent rather than constant, start instead with why a keyboard feels slow or laggy, which works through software, driver and hardware causes in the order they are worth checking.

How these guides are grouped

The core guides answer the question you probably typed into a search box. The diagnostic guides deal with a specific misbehaviour — a key that doubles, drops, sticks or never arrives. The technical guides explain the machinery underneath, including the honest limits of measuring anything from inside a web page.

Every guide links back to the tool it explains, and every claim about timing traces back to the formulas published on the measurement methodology page.

Core guides

Nine guides covering what latency is, how to measure it, how to judge the result, and how it differs from the terms it gets confused with.

What Is Keyboard Latency? What the word actually refers to, and the chain of delays sitting between a keypress and a character on screen. How to Test Keyboard Latency A repeatable procedure for running the test, plus the conditions that quietly ruin a result. What Is a Good Keyboard Latency? How to judge a number you just measured, and why the spread matters more than the median alone. How Keyboard Latency Is Measured The three timing channels this site uses, the formula behind each one, and what each one includes. Latency vs Polling Rate Why a higher polling rate shortens a wait rather than removing a delay — with the arithmetic shown. Latency vs Response Time Two terms used interchangeably in product copy that describe genuinely different things. Latency vs Reaction Time Why a reaction-time score is mostly you, and cannot be subtracted down to a keyboard figure. How to Reduce Keyboard Input Lag Changes that measurably help, changes that help only sometimes, and popular advice that does nothing. Why Does My Keyboard Feel Slow? Software, OS and hardware causes of a keyboard that lags or delays input — and how to tell them apart.

Diagnostic guides

Five guides for a specific misbehaviour: a key that doubles, a key that never arrives, a key that stays down, or a combination that refuses to register.

What Is Keyboard Ghosting? Why a keyboard can report a key nobody pressed, and which wiring designs are prone to it. Ghosting vs Key Rollover The difference between a phantom key appearing and a real key being silently dropped. What Is N-Key Rollover? What NKRO means, where the familiar six-key limit comes from, and what a browser can confirm. What Is Keyboard Chatter? Why one press sometimes registers twice, and what contact bounce and debounce have to do with it. How to Fix a Stuck Key Telling a physically stuck key from a stuck modifier or a software hold, and what to try for each.

Technical guides

Five guides on the machinery underneath — event timestamps, event cadence, measurement variance, and the parts of the chain no web page can see.

Browser Keyboard Event Timing What a keyboard event's timestamp represents, and where main-thread scheduling enters the measurement. Why Browser Tests Can't Measure Hardware The parts of the input chain a web page never observes, and what real hardware measurement requires. Polling Rate vs Browser Event Cadence Why the interval between browser events is not a reading of a USB polling rate, however tempting. Why Latency Results Vary Why the same keyboard scores differently across browsers, machines, and even two runs an hour apart. Keyboard Latency Glossary Definitions for every term used across the site, with the pairs people confuse set side by side.

What these guides deliberately do not claim

The boundary every guide respects

Everything measured on this site is observed from inside a web browser, after the operating system has already delivered the key event. That makes it a real and repeatable measurement of the browser input pipeline — and it makes it impossible to isolate switch actuation, keyboard firmware, matrix scanning, USB or Bluetooth transmission, driver scheduling, or display response time.

So you will not find a guide here telling you your keyboard's hardware latency, ranking named keyboards by measured milliseconds, or reading a USB polling rate out of browser event intervals. Those claims need instrumentation a web page does not have.

Read the full methodology and its limitations

Keyboard Testing Guides