Windows does not normally show hardware DPI
Windows exposes pointer-speed and acceleration settings, but those settings are not the same thing as the mouse sensor's configured DPI. The exact hardware value normally comes from the mouse manufacturer's software or an onboard profile.
Check the Windows pointer settings
Use Windows mouse settings to keep your pointer configuration consistent. If you are trying to measure DPI, avoid changing pointer speed or acceleration between trials.
Check the manufacturer utility
For supported gaming mice, the manufacturer's utility may display DPI stages and let you save them to a profile. This is the preferred method for finding the configured value.
Use the browser analyzer for an independent estimate
Move a known physical distance and repeat the measurement several times. The Mouse DPI Analyzer reports a browser-based estimate and statistics, not a sensor-register reading.
Windows acceleration and measurement
Pointer acceleration changes the relationship between physical movement and pointer movement. If consistency matters, use a controlled configuration and understand that browser measurements are affected by the input path between the mouse and web page.