Aspect Ratio Calculator
Result
| Aspect Ratio | ||
|---|---|---|
| New Width | ||
| New Height |
Share on Social Media:
Aspect Ratio Calculator — Resize Without the Squish
Every stretched thumbnail and squashed logo comes from the same mistake: changing one dimension without proportionally changing the other. This free aspect ratio calculator solves the missing dimension for any ratio — enter a width, get the correct height (or vice versa) — identifies the ratio of any pixel dimensions, and includes presets for every platform standard. Instant, in-browser, no signup.
The Math
new height = new width × (original height ÷ original width)
Scaling a 3000×2000 photo to 1200 wide: 1200 × (2000/3000) = 800 tall. To identify a ratio, divide both dimensions by their greatest common divisor: 3000×2000 → GCD 1000 → 3:2.
Platform Standards Cheat Sheet
| Ratio | Use | Common resolutions |
|---|---|---|
| 16:9 | YouTube, TV, presentations | 1280×720, 1920×1080, 3840×2160 |
| 9:16 | TikTok, Reels, Shorts, Stories | 1080×1920 |
| 1:1 | Instagram feed, profile images | 1080×1080 |
| 4:5 | Instagram portrait posts | 1080×1350 |
| 4:3 | iPad, legacy video, some photos | 1024×768, 2048×1536 |
| 3:2 | DSLR photos, prints | 3000×2000, 6000×4000 |
| 21:9 | Cinematic, ultrawide monitors | 2560×1080, 3440×1440 |
| 2:3 | Pinterest pins | 1000×1500 |
Where This Saves Real Time
- Responsive web design — compute CSS
aspect-ratiovalues and image heights for fluid layouts that never jump during load. - Video editing — set export dimensions that match the platform instead of getting letterboxed or cropped by the algorithm.
- Print — check whether a digital photo's ratio matches the print size (a 3:2 photo forced into an 8×10, which is 4:5, loses edges to cropping).
- Thumbnails and banners — resize source art to exact platform specs without distortion.
Cropping vs Scaling
Scaling preserves everything but requires the same ratio; changing ratio requires cropping (losing pixels) or padding (adding bars). When a 16:9 video must become a 9:16 short, plan the crop around the subject — the calculator tells you the crop window: a 1920×1080 source yields at most a 608×1080 vertical slice.
Free and Instant
Unlimited calculations locally in your browser, no account. Keep it open beside your editor or export dialog.