Aspect Ratio Calculator
Enter a width and height to get the aspect ratio in simplest form, resize an image or video to a new width or height without distorting it, and work out a screen's width and height from its diagonal for 16:9, 4:3, 21:9 and other ratios.
Aspect ratio calculator
Resize and keep the ratio
Screen size from diagonal
How to calculate aspect ratio
Divide width and height by their greatest common divisor. 1920 × 1080: the GCD is 120, so the ratio is 16:9. To resize while keeping the ratio, new height = new width × (height ÷ width): 1280 wide at 16:9 is 720 tall.
From a TV's diagonal: width = diagonal × 16 ÷ √(16² + 9²) = diagonal × 0.8716 for 16:9. A 65" TV is about 56.7" wide and 31.9" tall.
| Ratio | Common resolutions |
|---|---|
| 16:9 | 1280×720, 1920×1080, 2560×1440, 3840×2160 |
| 9:16 | 1080×1920 |
| 4:3 | 1024×768, 1600×1200 |
| 21:9 (approx.) | 2560×1080, 3440×1440 |
| 1:1 | 1080×1080 |
| 4:5 | 1080×1350 |
Common questions
How do I calculate aspect ratio?
Divide width and height by their greatest common divisor. 1920 × 1080 → 16:9.
What is the aspect ratio of 1080p?
16:9 (1920 × 1080).
How do I resize an image without stretching it?
Change one side and work out the other with the same ratio: new height = new width × original height ÷ original width.
How wide is a 65-inch TV?
About 56.7 inches wide and 31.9 inches tall for a 16:9 screen, not counting the frame.
What aspect ratio is Instagram?
Square 1:1, portrait 4:5 (1080 × 1350) and vertical 9:16 for Reels and Stories.
Sources
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General information, not financial, tax or legal advice. Check important numbers with the official source before acting on them.