Calculate aspect ratio

Calculate dimensions that preserve a chosen width-to-height ratio.

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ToolAspect Ratio Calculator
Input
Output
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Preview

How it works

An aspect ratio is width divided by height; preserving it scales one dimension from the other without changing the quotient. Given a target box, the fit or crop policy decides which dimension is constrained.

  • The ratio is dimensionless and applies across pixels, print units, and CSS boxes.

Worked example

HD Resolution
Calculate aspect ratio for a 1920x1080 display
Input
											Width: 1920
Height: 1080
Output
												Aspect Ratio Calculator
=======================

Original dimensions: 1920 x 1080
Aspect ratio: 16:9
Decimal ratio: 1.7778
GCD: 120

Closest standard ratio: 16:9 (diff: 0.0000)

Common sizes maintaining this ratio:
  480 x 270 (0.25x)
  960 x 540 (0.5x)
  1440 x 810 (0.75x)
  1920 x 1080 (1x)
  2880 x 1620 (1.5x)
  3840 x 2160 (2x)
  5760 x 3240 (3x)

When to use this

Video embeds, social-media exports, and responsive thumbnails calculate dimensions.

Edge cases

  • A zero height makes the ratio undefined.
  • Swapping width and height inverts the ratio.
  • Contain and cover preserve the ratio but create different unused or cropped areas.

References