Image·Updated 2026-04-22
Aspect Ratio Calculator
16:9, 9:16, 1:1, 4:5. Compute the matching new height or width.
Aspect Ratio Calculator
How it works
- 1.
Preset or custom
Pick a preset (16:9 video, 9:16 reel, 1:1 post, 4:5 portrait, 1.91:1 Open Graph) or enter your own starting dimensions.
- 2.
Enter one new side
Enter a new width or height. The other dimension is computed proportionally. GCD simplifies the ratio to the cleanest form (for example 1920×1080 = 16:9).
- 3.
Scale proportionally
Perfect for video export, social media assets, responsive images, or CSS aspect-ratio properties. One click copies width, height, or the ratio string.
FAQ
Which presets are included?+
16:9, 9:16, 4:3, 1:1, 3:2, 21:9, 4:5, 1.91:1, 2:3. Custom ratios are fully supported.
How is the ratio simplified?+
By the greatest common divisor (GCD) of width and height.
Why 1.91:1 for Open Graph?+
1200×630 is the official OG spec — that produces a 1.91:1 ratio.