Mouse DPI Test
Measure your mouse's real DPI by dragging a known physical distance.
Measured DPI
—
Use a ruler and move the mouse in one straight sweep. Turn off pointer acceleration ("Enhance pointer precision" on Windows) first, or the result will be wrong.
Your test runs locally in your browser. No device data is uploaded.
How to use the DPI test
Set the distance you are going to move, put a ruler next to your mouse, then press inside the test area and drag straight to the right by exactly that distance before releasing. The test counts the pixels the cursor travelled and divides by the physical distance you moved. Repeat a few times and take the middle result.
Why you have to supply the distance
DPI means dots per inch of physical movement, and a browser has no way to know how far your hand actually moved. It only ever sees how many pixels the cursor covered. Supplying the real-world distance is the only way to convert one into the other, which is why every browser-based DPI tool works this way.
This also means the accuracy of the result depends on how accurately you measure and how straight you drag.
Getting a trustworthy number
Turn pointer acceleration off first. On Windows that is Enhance pointer precision in the mouse settings; on macOS it is the pointer acceleration curve, which cannot be fully disabled without third-party software. With acceleration on, the pixels-per-inch ratio changes with how fast you move, and the result becomes meaningless.
Display scaling also shifts the number, since a scaled desktop reports different pixel counts. A result within a few percent of your mouse's setting is normal; being out by half or double almost always means acceleration is still enabled.
Frequently asked questions
- Why do I have to measure the distance myself?
- DPI is dots per inch of physical movement, and a browser has no idea how far your hand actually moved, only how many pixels the cursor covered. Supplying the real-world distance is the only way to turn pixels into DPI, which is why every browser DPI tool works this way.
- How do I get an accurate result?
- Turn off pointer acceleration first, which is Enhance pointer precision on Windows, because it changes the pixels-per-inch ratio depending on how fast you move. Use a ruler, drag in one straight sweep at a steady speed, and repeat a few times.
- The result does not match my mouse's advertised DPI.
- Some difference is expected. Pointer acceleration, display scaling and the sensor's own tolerance all shift the number, and many mice are a few percent off their nominal setting. Within about 5% is normal; out by half or double suggests acceleration is still on.
- Can I change my DPI here?
- No, a web page cannot. DPI is set in the mouse itself, usually with a button on the mouse or through its vendor software.