Three reliable approaches
- Manufacturer software: for supported models, look in sensitivity, DPI or performance settings. Examples include Logitech G HUB, Razer Synapse and other mouse utilities.
- Onboard DPI button: some mice cycle through preset stages. A button changing the cursor speed does not tell you the exact DPI unless you know the stages.
- Product manual: check official documentation for factory DPI stages and whether you previously customized them.
Do not confuse Windows pointer speed with mouse DPI
Changing the operating system pointer speed does not necessarily change the sensor's configured DPI. Games using raw mouse input can behave differently from the desktop cursor. Verify the mouse setting rather than deriving it from Windows slider position.
Next step
Once you know DPI, enter it with the in-game sensitivity in the eDPI Calculator. If you switch DPI, use the DPI matching tool.