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Photography

Aspect Ratio Calculator

Aspect Ratio Calculator

Simplify a width×height ratio and scale to a target width or height.

Results update as you type.

How to use

Enter the source width and height in pixels. Optionally set a target width or height to scale the other side while keeping the ratio.

Formula

ratio = width ÷ height (reduced by GCD)
scaled height = target width × (height ÷ width)
scaled width = target height × (width ÷ height)

Worked example

  1. 1920×1080 simplifies to 16:9. Scaling to width 1280 keeps height 720.

Assumptions

  • Inputs are positive pixel sizes.
  • The reduced ratio uses integer GCD; very odd sizes may not land on a common named ratio.

FAQs

What does 16:9 mean?
Width is 16 parts and height is 9 parts. A 1920×1080 frame is 16:9.
How do I pick a print size?
Set a target width or height. The other side is scaled to keep the same ratio. Pair this with the Print Size tool for DPI.
Why is my ratio not 4:3 or 16:9?
Camera sensors and crops often use other ratios. The tool shows the exact reduced ratio for your pixels.
Can I enter only one target side?
Yes. Leave the other target blank and the tool fills the matching side.

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