Mouse DPI Tester

Measure true hardware CPI, detect sensor deviation, and calibrate exact 360° physical turn distances.

Target DPI:
Distance:
Measured CPI
---CPI
Hardware True
Discrepancy
0.0%
Raw Counts0Pulses Sampled
System StatusREADYPointer Lock OK
1
Place Desk RulerLine up a physical ruler against the edge of your mouse.
2
Click & Hold PadPress & hold Left-Click anywhere inside this card.
3
Slide 1.00" & ReleaseMove mouse along desk ruler, then release to calculate.
Press & Hold Left-Click to MeasureLocks cursor & samples raw optical sensor pulses
eDPI & 360° Turn DistancesCalibrated automatically from measured CPI
ValorantYaw: 0.07
Sens:
360° Distance:-- cm
CS2 / ApexYaw: 0.022
Sens:
360° Distance:-- cm
Overwatch 2Yaw: 0.0066
Sens:
360° Distance:-- cm
Fortnite (%)Yaw: 0.00555
Sens %:
360° Distance:-- cm
Sensor Calibration Reference

DPI Deviation & Focal Height Comparison

Comparing real-world CPI accuracy and step adjustment precision across modern optical sensors.

Pro Tier Hierarchy
Hardware ModelDPI Deviation RangeMax Native DPIStep PrecisionOur rating
1
Razer Focus Pro 35K Gen-2Flagship Optical
< 1.0% Deviation35,000 DPI Max1 DPI Step Tuning
Tier S+ (Pro Grade)
2
Logitech HERO 2Flagship Optical
< 1.5% Deviation44,000 DPI Max10 DPI Step Tuning
Tier S (Pro Grade)
3
PixArt PAW3395Esports Standard
< 2.0% Deviation26,000 DPI Max50 DPI Step Tuning
Tier A (Esports Standard)
4
Budget Optical (PAW3327 / PMW3325)Entry Level
3.5% – 7.0% Deviation12,000 DPI Max100 DPI Step Tuning
Tier D (Entry Level)
Ratings are our editorial opinion based on manufacturer specs.
Related Engineering GuideTrue CPI vs Sensor Deviation: Why 800 DPI Feels Different Across Mice
Read CPI Deviation Guide
DPI Calibration Science

Understanding Mouse CPI & DPI Deviation

Everything you need to know about hardware step counts, sensor accuracy, and skate focal distance.

CPI vs Labeled DPI

Technical Precision

DPI (Dots Per Inch) is a printer term. Mouse sensors count digital steps per inch (CPI). A mouse set to 800 DPI might actually report 835 CPI due to glass or PTFE pad thickness tolerances.

Lift-Off Distance (LOD) Impact

Focal Distance

Aftermarket glass skates or extra thick PTFE feet alter the distance between the optical lens and mousepad, shifting the effective hardware CPI by up to 5%.

eDPI & 360° Turn Distance

Effective Sensitivity

eDPI (Effective DPI) is calculated as DPI × In-Game Sensitivity. Matching your true cm/360° turn distance across all tactical shooters preserves long-term aim muscle memory.

Pointer Lock Raw Movement

Zero OS Acceleration

This tool uses the browser Pointer Lock API to directly read hardware movementX counts, bypassing Windows mouse acceleration (Enhanced Pointer Precision) and screen resolution limits.

FAQ Reference

Mouse DPI & CPI Frequently Asked Questions

What is mouse DPI deviation?
DPI deviation is the difference between your selected DPI setting (e.g. 800) and the sensor's actual hardware CPI output (e.g. 835 CPI) caused by lens height tolerances.
How do I measure my true mouse DPI with a physical ruler?
Place a physical ruler beneath your mousepad. Measure the exact distance you move your mouse horizontally (e.g., 2 inches) and compare your configured DPI against the hardware movement count reported by the tool.
What DPI is best for competitive FPS gaming (800 vs 1600)?
1600 DPI offers slightly lower sensor input latency than 400 or 800 DPI without introducing sensor noise or smoothing. Most modern competitive pros play at 800 or 1600 DPI.
Why does 800 DPI feel slower on high-resolution 1440p and 4K monitors?
Because 800 DPI moves your cursor 800 pixels per inch. Across a 4K display (3840 horizontal pixels), you must physically move your mouse nearly 5 inches to traverse the screen, compared to only 2.4 inches on a 1080p monitor.