Mouse Lab // Physical Travel Calibration
MOUSE DPI TEST & ESTIMATOR
Estimate mouse DPI by moving your mouse a physical distance that you measure on your desk or mouse pad. GearCheck Lab compares that known distance with browser-observed Pointer Lock movement, saves repeated runs, and shows average DPI and run-to-run consistency.
LOCAL DIAGNOSTICYour movement samples and entered distance stay in this browser session on this page.
How to measure mouse DPI online
- Choose a straight physical path on your desk or mouse pad and measure it with a ruler or tape measure. Ten centimetres or more is a practical starting length.
- Enter that exact distance above. If your mouse software shows a configured DPI, you can enter it as an optional comparison value.
- Place the mouse at your marked start point, click Start DPI Run, then move the mouse smoothly in one straight direction until it reaches the measured end point.
- Press Space to save the run. Repeat at least three times from the same start and end marks.
- Use the average and run spread rather than trusting one measurement. Large run-to-run variation usually means the physical movement or browser input path was not consistent enough.
What this DPI result means
DPI means dots per inch, but a browser cannot ask most mice for their sensor's configured hardware DPI. This tool therefore calculates an estimate: browser-observed movement units divided by the physical distance you tell us you moved the mouse.
When the browser supports it, GearCheck Lab requests Pointer Lock with unadjusted movement. If that request is unavailable or rejected, the page falls back to normal Pointer Lock and labels the method accordingly.
The result is best used to compare repeated runs or check whether a configured setting is in the expected neighbourhood. It is not a firmware readout or laboratory calibration certificate.
Why your estimate may differ from the configured DPI
- Physical measurement error: moving 9.7 cm when the input says 10 cm changes the result.
- Pointer processing: operating-system acceleration, scaling, drivers or browser behaviour can affect movement values when raw/unadjusted input is not available.
- Path shape: this estimator uses the net movement vector. A curved path or reversing direction makes the physical path and browser displacement less comparable.
- Surface and sensor behaviour: lift-off, poor tracking surfaces, wireless instability or sensor smoothing can affect repeated measurements.
- Browser support: Pointer Lock and unadjusted movement support vary between browser and operating-system combinations.
How to improve measurement quality
Use the same browser, port or wireless connection and mouse setting for every comparison. Disable operating-system pointer acceleration if you are deliberately testing processed Pointer Lock rather than raw/unadjusted input. Use a longer physical path where practical, keep the mouse flat, and move smoothly without lifting it.
If one run is far away from the others, clear the runs and repeat rather than averaging a visibly bad pass into the result. Three to five closely grouped runs are more informative than one exact-looking number.
Worked DPI calculations and result interpretation
The estimator converts the entered distance to inches, then divides the net browser movement by that distance. For example, 10 cm is 3.937 inches. If the browser reports 3,150 movement units across that measured path, the estimate is approximately 800 DPI.
estimated DPI = net browser movement ÷ measured distance in inches
3,150 ÷ (10 ÷ 2.54) = 800.1 DPI
| Result pattern | What it supports | What to do next |
|---|
| Three to five closely grouped runs | The physical path and browser input method were repeatable enough for a useful comparison. | Use the average as an estimate, recording the browser, input method and mouse setting alongside it. |
| Wide run spread | The runs do not agree closely enough for a confident estimate. | Re-mark the endpoints, use a longer path, keep the mouse flat and repeat without reversing direction. |
| Processed Pointer Lock fallback | The browser supplied movement, but operating-system acceleration or scaling may still affect it. | Compare only runs made with the same browser, system settings and reported input method. |
| Estimate differs from configured DPI | The difference may come from physical-distance error, pointer processing, surface tracking or device tolerances. | Check the selected unit, repeat the same path, and compare the percentage difference across several runs. |
If an 800 DPI setting produces a 760 DPI average, the displayed comparison is −5.0%: (760 − 800) ÷ 800 × 100. That difference is troubleshooting evidence, not proof that the sensor is misconfigured.
Mouse DPI test FAQ
Can a website read my exact mouse DPI?
Usually no. Standard browser APIs expose pointer movement, not the mouse sensor's firmware DPI setting. This page estimates DPI from a distance you physically measure.
Why does GearCheck Lab use Pointer Lock?
Pointer Lock lets the browser report relative mouse movement even after the hidden pointer would otherwise reach a screen edge. Some browsers also allow the page to request unadjusted movement, which can reduce operating-system pointer processing.
Is a 10 cm measurement better than 2 cm?
Usually, because the same one- or two-millimetre ruler or endpoint error represents a smaller percentage of a longer measured path. Use a distance that fits your available desk space and can be repeated accurately.
What is run spread?
The spread shown here is the sample standard deviation of your saved DPI estimates. A smaller spread means your repeated browser measurements are grouping more closely; it does not prove the mouse sensor itself has that exact precision.
Does this change my mouse DPI?
No. GearCheck Lab only observes browser input. Change DPI in the mouse manufacturer's software, on-device controls or supported operating-system settings.
Related mouse diagnostics
