Aspect Ratio Calculator
Simplify a ratio, solve for a missing dimension, and check what a size works out to.
With the ratio locked, editing either dimension recalculates the other.
Common sizes
Aspect ratio
16:9
- Decimal
- 1.7778
- Orientation
- Landscape
- Megapixels
- 2.07 MP
- Matches
- 16:9 — Widescreen / HD
Shape preview
- The ratio is reduced by greatest common divisor, so 1920×1080 and 1280×720 both report 16:9.
- Some real sizes have no tidy ratio — a 1200×630 Open Graph image is 40:21, close to but not exactly 16:9.
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The Aspect Ratio Calculator reduces any width and height to its simplest form using the greatest common divisor, so 1920×1080 and 1280×720 both come out as 16:9. Alongside the ratio it reports the decimal value, orientation, total megapixels, and whether the shape matches a recognised standard.
Lock a ratio and the calculator works the other way: type either dimension and the matching one is computed, which is the arithmetic behind “maintain aspect ratio” in an image editor. Presets cover video, photography, cinema and social formats. Worth knowing that not every real-world size reduces neatly — the standard 1200×630 Open Graph image is 40:21, close to 16:9 but not the same, because it was chosen for social card layout rather than to match a video ratio.
FAQ
Enter its width and height. The ratio is reduced by greatest common divisor, so 1920×1080 and 1280×720 both report 16:9, along with the decimal value and orientation.
Lock a ratio, then type either dimension and the other is calculated for you. That is the arithmetic behind "maintain aspect ratio" in image editors.
It is 40:21 — close to 16:9 but not identical. The standard Open Graph size was chosen for social card layout rather than to match a video ratio, which is why it reduces to an odd-looking fraction.
1:1 or 4:5 for Instagram feed posts, 9:16 for stories and reels, and 1.91:1 (roughly 1200×630) for Open Graph link previews. All are available as presets.
Width times height divided by a million — the total pixel count. It is what camera specifications quote and a rough proxy for uncompressed file size.
No. It is arithmetic running in your browser.