Click Calibrate to set up your screen, then click any two points to measure. Hold Shift to draw a straight line.
CCalibrate
FFullscreen
DDark Mode
1-4Switch Unit
ShiftAxis-lock
EscCancel
DelDelete Last
MMove tool
LLine mode
AAngle mode
PPath mode
RRect mode
OCircle mode
NAnnotate
XDelete tool
EnterFinish path
SSnap
Ctrl+SScreenshot
Calibrate your ruler.
Detecting your device...
Detected Device—
PPI—
Resolution—
Pixel Ratio—
Confidence—
Tip: Monitors marketed as 24" often measure between 23.5" and 23.8" depending on the brand. If the ruler is not perfectly accurate, switch to the Screen Size tab to enter your exact diagonal size, or use Credit Card calibration for the best accuracy.
Enter your screen's diagonal size in inches. You can find this in your device specifications or on the original packaging.
inches
Common sizes:
Tip: Commercial screen sizes are rounded. Laptops marketed as 15" often measure between 15.0" and 15.6", and 24" monitors often measure between 23.5" and 23.8" depending on the manufacturer. If unsure, calibrate using a standard Credit Card.
Place your physical credit card on the screen, matching it inside the blue border of the overlay card. Resize the overlay below until they match exactly.