Mouse DPI Analyzer

How to measure your mouse DPI

1. Enter the distance you are going to move, for example 5 cm or 2 inches. Longer is more accurate. If you know the DPI set in your mouse software, type it too so the deviation can be shown.
2. Put a ruler on the desk next to the mouse and line up the front edge of the mouse with a mark, or line it up with the edge of your mouse pad.
3. Click inside the box. The pointer is captured so it cannot hit the edge of the screen.
4. Move the mouse slowly in a straight line to the right, exactly the distance you entered. The bar shows raw movement counts as they arrive.
5. Press Space or click to finish. Repeat two or three times; the result averages your runs. Press Esc to release the pointer at any time.

What the results mean

Measured DPI is the number of movement counts your mouse sent divided by the distance you moved in inches. A mouse set to 800 DPI should send about 800 counts per inch, so a 2 inch move produces about 1600 counts.

Deviation compares the measured value with the DPI you typed in. Within about 5% is normal: your hand is not a machine and the sensor has tolerances. A deviation of 10-20% is common on cheap mice and on some sensors at very high DPI settings; it is not a fault, but if you want exact in-game sensitivity you can enter the real value instead of the nominal one in sensitivity calculators.

A result that is half or double what you expected usually means the operating system is scaling your movement (see the fixes), not that the mouse is wrong. Run the test again after checking pointer speed and acceleration.

What mouse DPI means and why it varies

DPI (dots per inch, also called CPI, counts per inch) is how many movement reports a mouse sensor sends when you move it one inch. At 400 DPI an inch of hand movement moves the pointer 400 pixels on a 100% scaled screen; at 1600 DPI, four times further. Gamers care because sensitivity calculators and aim trainers assume the stated DPI is accurate, and many sensors are off by 5-10%. The same model can measure differently depending on the surface, the firmware and the DPI step chosen, which is why reviewers test the "true" DPI.

This DPI analyzer uses the browser's pointer lock with raw, unaccelerated movement where the browser supports it (Chrome and Edge on Windows and macOS), so operating system pointer speed and acceleration do not affect the count. In other browsers it falls back to normal movement and asks you to set Windows pointer speed to the 6th notch and turn off "Enhance pointer precision", which gives a 1:1 ratio.

Tips for an accurate reading

Move slowly and in a straight line; sideways wobble adds counts. Use a longer distance (10 cm or 4 inches) for a smaller error from your start and stop points. Use the edge of the mouse feet as a reference, not the rounded shell. Test on the mouse pad you actually use, because cloth and hard pads can differ by a few percent. Repeat three times and read the average. If you are comparing DPI steps, test each one the same way; if the ratio between steps is correct (for example 800 to 1600 doubles exactly), the sensor is consistent even if the absolute value is a little off.

Common problems and fixes

The result is about half or double what I set

Your operating system is scaling the movement. On Windows, set Settings > Mouse > pointer speed to the middle (6 of 11) and untick "Enhance pointer precision" in Additional mouse settings. On macOS, this browser may not expose raw counts; try Chrome.

The pointer does not lock or escapes the box

Pointer lock needs a direct click and is blocked inside some embedded frames. Open the page directly, click once inside the box, and allow the browser's pointer-lock prompt. Press Esc to release it.

The count keeps rising when the mouse is still

The sensor is jittering, usually because the surface is reflective, patterned or dirty, or the mouse is lifted a little. Clean the sensor lens and test on a plain mouse pad.

Deviation is more than 10%

Common on budget sensors and at DPI steps above 3200. Use the measured value in sensitivity calculators, or pick a DPI step that measures closer to its label. Update the mouse firmware; some updates fix DPI tracking.