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Keyboard Latency Test

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Overview

Want to know how much faster your mechanical keyboard responds compared to your old one? Just bought a new keyboard and want to verify it performs the same? Tweaked your system settings and want to see if latency actually dropped? On escwasd's Keyboard Latency Test, swap keyboards, click Reset, press the same keys, and get a side-by-side relative comparison — all on the same machine, same browser, same conditions.

How to Use

  1. Page loads in standby — press any keyboard key to start recording automatically.
  2. Watch the right panel update in real time with current latency, average, best/worst.
  3. The green curve below shows each keystroke's latency with a yellow dashed average line.
  4. Test auto-stops when target sample count is reached — review your rating and stats.

Feature Details

This tool measures browser event processing latency — the time from when the operating system delivers a keyboard event to when your JavaScript callback executes. By running multiple keyboards on the same computer under identical conditions, the relative differences in their measured latency directly reflect real performance gaps. The tool records each keystroke with sub-millisecond precision, computes average latency, standard deviation (jitter), and consistency percentage, then displays everything on a real-time green curve chart.

Features

Real-time latency measurement: sub-millisecond precision per keystroke.
Full statistics: average, best/worst, standard deviation (jitter), consistency %.
Estimated polling rate: computed as 1000 ÷ avg latency for an intuitive speed gauge.
Live curve chart: green latency line + yellow average line, spikes visible instantly.
Rating system: LEGEND / GREAT / GOOD / AVERAGE / BELOW AVG based on average latency.
Flexible sample size: 10 / 20 / 50 / 100 — more samples = more stable estimates.

Use Cases

  • Keyboard swap test: test old and new keyboards back-to-back on the same machine.
  • Same-model verification: compare two identical keyboard models for consistency.
  • Used/refurbished inspection: verify a second-hand keyboard against a known-good unit.
  • System optimization check: re-test after closing background apps to confirm latency improved.
  • Peripheral roundup: test multiple keyboards on the same PC for quantifiable relative data.

FAQ

How do I compare two keyboards?

Plug in the first keyboard and complete a test, note the average latency. Unplug it, plug in the second, click Reset, and test again. Compare the two averages — a difference under 1-2ms means they perform similarly; over 3ms indicates a real gap.

Why must I compare on the same machine?

Latency is influenced by CPU speed, OS scheduler, browser version, and more. Only by testing both keyboards on the same computer, same browser tab, back-to-back, can external factors be held constant for accurate comparison.

How should I interpret estimated Hz?

estimated Hz = 1000 ÷ average latency (ms). It converts latency into a more intuitive gauge. On the same machine, higher estimated Hz means snappier response. Note this is NOT the same as your keyboard's USB hardware polling rate.