Mouse Jitter Test

1. Choose a duration: 3, 5 or 8 seconds.
2. Place the pointer in the test area and hold your hand as still as possible.
3. Wait for the countdown to finish.
4. Read the RMS and maximum deviation, and repeat to compare.

Lower RMS means a steadier pointer. The tool measures pointer variation as the browser sees it, which includes hand tremor, surface vibration and the mouse, so it is not a measurement of the sensor alone.

Resting your hand fully on the mouse and a stable surface will usually give a lower score.

The test reports RMS deviation, which is a single number for how far the pointer wandered from its average position, in pixels. Lower means steadier.

Imagine you hold still for 5 seconds at 800 DPI and see an RMS of about 1 px with a maximum of 3 px. You then raise the DPI to 3200 and repeat the test. The same small hand tremor now moves the pointer roughly four times as far, so the RMS may rise noticeably. Nothing is wrong with the mouse: the pointer is simply more sensitive to small movements.

To make a fair comparison, test each setting two or three times on the same surface, with the same grip, and compare the typical result rather than the best or the worst.

• Rest your forearm. Supporting your arm on the desk reduces tremor and gives a lower RMS.
• Use a firm surface. A wobbly desk or a soft pad adds vibration that the test cannot tell apart from your hand.
• Do not grip too tightly. Tension increases small movements.
• Test at more than one DPI. If jitter only rises at very high DPI, lowering the DPI and raising your in-game sensitivity may suit you better. See DPI vs sensitivity.
• Do not diagnose a sensor from one test. The browser measures the whole chain of hand, surface, mouse and system, so repeat on another surface or mouse before drawing conclusions.

If you want to look at direction and path instead of stillness, try the movement tester.

Does jitter mean my sensor is bad?

Not by itself. Hand movement and desk vibration also contribute. Try again on a firm surface.

What is RMS deviation?

Root mean square deviation summarises how far the pointer wandered from its average position, in pixels.

Can high DPI increase jitter?

A higher DPI makes small movements cover more pixels, so the same hand tremor can look larger.