Aspect Ratio Calculator
Find and scale aspect ratios
Find aspect ratio
Scale dimensions
Presets:
Fill in 3 of the 4 fields. The missing one is calculated automatically.
Fill in exactly 3 fields (original width, original height, and one new dimension).
Enforce aspect ratio
Aspect Ratio
:
Presets:
Enter the ratio and one dimension. The other updates automatically.
How it works
- Find aspect ratio: Enter width and height to get the simplified ratio (e.g. 1920×1080 = 16:9)
- Scale dimensions: Change one dimension and the other updates automatically to keep the ratio the same
- Enforce aspect ratio: Set a ratio and one dimension, the other is calculated to match
What is an aspect ratio?
An aspect ratio expresses the proportional relationship between width and height as two integers reduced to their lowest common form. A 1920×1080 frame and a 640×360 frame are both 16:9 because dividing both sides by their GCD (greatest common divisor) gives the same pair. The ratio tells you the shape, not the size.
Common aspect ratios
- 16:9 - universal widescreen standard for HD/4K TVs, monitors, and video (1920×1080, 2560×1440, 3840×2160)
- 4:3 - classic TV and early computer monitors; still common in tablets
- 21:9 - ultrawide cinema and gaming monitors (2560×1080, 3440×1440)
- 1:1 - square format used in social media profile images and Instagram
- 3:2 - traditional 35 mm film and most DSLR/mirrorless cameras
- 9:16 - vertical video (TikTok, Reels, Stories)
- 2.39:1 - anamorphic cinema widescreen (sometimes written 2.35:1)
The math
To simplify a ratio, divide both width and height by their GCD. To scale while preserving the ratio, multiply or divide both dimensions by the same factor.
ratio = W : H (both divided by GCD)
scaled W = original W × (target H / original H)
scaled H = original H × (target W / original W)