Mouse DPI Analyzer

Estimate your mouse's true CPI by moving it a measured distance. Pointer-locked, with a built-in check for pointer acceleration.

How the estimate works

Set the distance you'll move (measure it with a ruler), click the pad to lock the pointer, move your mouse exactly that far in a straight line, then click again. We sum the raw movement, scale it to device pixels, and divide by the distance in inches to get counts per inch.

It's an estimate — and that's the honest answer

This can't match a sensor's rated CPI as closely as the polling-rate test matches reported rate. Its accuracy hinges on your distance measurement and on acceleration being disabled. Running two passes at different speeds is the trust check: consistent results mean acceleration is off and the number is meaningful.

FAQ

Can a browser really measure mouse DPI?

Only as an estimate. There's no API that reports a mouse's DPI/CPI, so we derive it from a physical move you measure with a ruler. It depends on you measuring accurately and on pointer acceleration being off.

Why must I disable pointer acceleration?

With "enhance pointer precision" (Windows) or mouse acceleration (macOS) on, the movement the browser reports is no longer proportional to physical motion, so the CPI comes out wrong. Run two passes at different speeds — if they diverge by more than 10%, acceleration is almost certainly on.

What's the difference between DPI and CPI?

CPI (counts per inch) is the technically correct term for a mouse sensor; DPI (dots per inch) is a display term the industry borrowed. We label the result DPI because that's what you'll see on the box, but it's really CPI.

Why does it need pointer lock?

Pointer Lock hides the cursor and lets us read raw movement deltas without the pointer hitting a screen edge and clipping the measurement mid-move.