Aspect Ratio Calculator
Calculate aspect ratios and find new dimensions while maintaining proportions.
Ratio
Decimal
Closest Common
Ratio:
Common Aspect Ratios
How It Works
Enter original width and height to get the aspect ratio. Or enter an aspect ratio and one dimension to calculate the other. Perfect for responsive design.
**Aspect Ratio Calculator — Maintain Perfect Proportions**
Aspect ratio is the proportional relationship between an image's width and height. Maintaining the correct aspect ratio prevents distortion when resizing images or designing responsive layouts. Our calculator handles all aspect ratio problems instantly.
**What Is Aspect Ratio?**
Aspect ratio is expressed as width:height. A 1920×1080 image has an aspect ratio of 16:9 (the standard HD/widescreen ratio).
Formula: Ratio = Width : Height (simplified by GCD)
**Common Aspect Ratios**
| Ratio | Common Uses |
|---|---|
| 1:1 | Instagram posts, profile photos |
| 4:3 | Traditional TV, old monitors, standard photography |
| 16:9 | HD video, modern monitors, YouTube, presentations |
| 16:10 | Widescreen laptops |
| 3:2 | DSLR photos (35mm film standard) |
| 2:1 | Panoramic photography, Twitter header |
| 9:16 | Vertical video (Instagram/TikTok Stories, YouTube Shorts) |
| 21:9 | Ultrawide cinema |
**Three Calculation Modes**
1. **Find ratio from dimensions** — Enter W and H to get ratio
2. **Find height from ratio + width** — Enter ratio and width
3. **Find width from ratio + height** — Enter ratio and height
**Responsive Web Design**
CSS has a padding-bottom trick to maintain aspect ratios for responsive containers:
For 16:9: `padding-bottom: 56.25%` (9/16 × 100)
For 4:3: `padding-bottom: 75%`
For 1:1: `padding-bottom: 100%`
Modern CSS uses the aspect-ratio property: `aspect-ratio: 16 / 9;`
**Photography and Printing**
Standard print paper (A4, Letter) has different ratios than digital sensors. A 3:2 camera image won't fit perfectly on an 8×10 print without cropping. Our calculator helps plan crops to avoid losing important elements.