Mouse DPI Test

Measure your mouse's real DPI right in the browser: say how far you will move the mouse, lock the pointer, and slide it that distance along a ruler. Nothing is installed and nothing leaves your device.

Measure the stretch you will move over

Lay a ruler along the desk beside the mouse, put the mouse at the start and note where you will stop. Longer is better: over 20 cm a millimetre of error barely matters, over 5 cm it ruins the result. You do not have to stop exactly on the mark - after the run you can correct the distance you actually covered.

Press start, then slide the mouse along the ruler for about 20 cm. The cursor disappears while it runs - that is normal.

  • The cursor disappears while measuring - that is the pointer lock doing its job. Watch the ruler on the desk, not the screen.
  • Move in one straight line, slowly and evenly, and keep the mouse flat: lifting it or flicking it loses counts.
  • One run is not a result. Make three and compare: a spread under 2% means you measured carefully.

What Mouse DPI Actually Is

The measurement above divides the counts your sensor reported by the distance you moved. Here is what that number means, why it may not match the box, and what to do with it.

DPI, CPI and what the sensor reports

DPI - dots per inch, or CPI, counts per inch - is how many steps of movement the sensor reports for every inch the mouse travels. At 800 DPI an inch of desk produces 800 counts. It is a property of the sensor and its current setting, not of the screen, the cable or the operating system.

DPI is not sensitivity

Sensitivity is a multiplier applied to those counts afterwards, by Windows, macOS or the game. Halving the DPI and doubling the sensitivity moves the cursor the same distance, but the mouse now reports half as many steps, so the movement is coarser. Set DPI where the sensor is happy and leave sensitivity to do the fine-tuning.

Why acceleration ruins the measurement

Pointer acceleration makes the cursor travel further when you move fast. The counts the browser sees are then scaled by how quickly you moved, and dividing them by a distance no longer gives DPI. This page asks the browser for unadjusted movement, which bypasses the system's scaling; when it is refused, the result carries a warning.

What DPI to use

There is no correct value, only a comfortable one. Shooter players commonly sit between 400 and 1600 so that big arm movements aim precisely; office and design work suits 800 to 1600 on a normal monitor and more on a 4K one, where everything is physically smaller. Very high settings mostly buy headroom, not accuracy.

How to change your DPI

Many mice have a button behind the wheel that steps through preset levels, usually with an LED colour per step. Gaming mice let their software - Logitech G HUB, Razer Synapse, SteelSeries GG, Corsair iCUE - set exact values, and most store them in the mouse itself so they survive a different computer. Office mice often have one fixed setting and only sensitivity to adjust.

Polling rate test
DPI is how finely your mouse sees. Polling rate is how often it reports. Measure yours in a few seconds.
Test polling rate
Cursor drift test
Check whether the cursor creeps while your hand is off the mouse - a sensor or surface problem that DPI cannot explain.
Check for drift
Full mouse test
Buttons, wheel, double click and click speed, all on one page.
Open the mouse test

Mouse DPI Questions

DPI stands for dots per inch: the number of movement steps the mouse sensor reports for every inch it travels across the desk. Some makers call it CPI, counts per inch, which is the more accurate name for the same thing. A higher figure means the cursor covers more screen for the same hand movement.
DPI happens in the mouse, sensitivity happens in the computer. The sensor produces counts, then Windows, macOS or the game multiplies them before moving the cursor. Two setups can feel identical while one reports twice as many steps as the other - and the one reporting more steps tracks small movements more precisely.
Usually because the measurement is imperfect: a stretch measured a few millimetres out, a slightly curved path, or the mouse lifting at the end. Measure over 20 cm or more and run it three times. If the result stays 10% or further from the claim, the mouse really is off - budget sensors are often several percent out, and some are calibrated only for one of their preset levels.
It does, unless the browser grants unadjusted movement. This page always asks for it, and Chrome and Edge on Windows and macOS normally give it. When the request is refused the page says so above the result, because the number then includes whatever scaling the system applied. Turning acceleration off in the system settings removes the doubt entirely.
Most competitive shooter players use 400 to 1600 DPI with a low in-game sensitivity, so a whole turn takes a sweep of the forearm rather than a flick of the wrist. Slower games and strategy titles are comfortable higher. What matters more than the number is keeping it constant, since your aim is muscle memory trained on one setting.
On a 1080p screen, 800 to 1200 DPI lets you cross the desktop without lifting the mouse while still hitting small buttons. On a 1440p or 4K monitor everything is physically smaller, so 1600 or more saves your arm. Photo and design work benefits from a higher DPI for precise selections, with sensitivity turned down to compensate.
Look for a small button behind or below the scroll wheel: pressing it steps through the preset levels. Gaming mice add software - Logitech G HUB, Razer Synapse, SteelSeries GG, Corsair iCUE - where exact values can be set and stored in the mouse. If your mouse has neither, its DPI is fixed and only the system's pointer speed can be changed.