Aspect Ratio Calculator for Screens, Images and Video
Simplify any width and height into a standard screen, image or video aspect ratio. Everything runs locally in your browser.
How to calculate and compare screen aspect ratios
Enter the width and height in the same unit. The calculator reduces both numbers using their greatest common divisor and also shows the decimal ratio. Common results include 16:9 for HDTV and most monitors, 16:10 for productivity displays, 4:3 for older media and 21:9 for ultrawide screens.
Where aspect ratio matters
Use the ratio when fitting a video, image or game to a display without stretching. A source and screen with different ratios will create letterboxing, pillarboxing or cropping. The simplified ratio describes shape only; it does not tell you the physical size, pixel density or native resolution.
Privacy and accuracy
The calculation runs in your browser and does not upload the dimensions you enter. Results are estimates based on the values supplied, so treat them as planning guidance and verify the manufacturer's specification before making a purchase or calibration decision.