70 toolsAbout Aspect Ratio Calculator
The Aspect Ratio Calculator finds the simplified ratio between a width and height — like 1920×1080 reducing to 16:9 — and shows the equivalent decimal value.
Once you have a ratio, use the second section to scale to a new size: type a new width and the matching height is calculated automatically (or the other way around), so the proportions always stay locked.
Quick-select buttons cover the most common screen and photo ratios — 16:9, 9:16, 4:3, 3:2, 1:1, 21:9, 5:4, and 2:3 — useful for video, photography, printing, and responsive design work.
Everything calculates instantly in your browser as you type. Nothing is uploaded.
How to Use Aspect Ratio Calculator
Enter a width and height to find their simplified ratio (e.g. 1920 × 1080 → 16:9), or pick a common preset.
The decimal ratio and a scaled proportion preview update instantly.
In the second section, type a new width or height — the other field is calculated automatically to keep the same ratio.
Copy the ratio or the calculated dimensions with one click.
Examples
Frequently Asked Questions
How is the aspect ratio calculated?
The width and height are divided by their greatest common divisor (GCD), reducing them to the smallest whole-number ratio — for example 1920×1080 reduces to 16:9 because GCD(1920, 1080) = 120.
How do I resize an image without distorting it?
Find the ratio of your original dimensions in the first section, then enter your target width (or height) in the second section — the matching height (or width) is calculated automatically so the image scales proportionally.
What is the difference between 16:9 and 16:10?
16:9 (1.778) is the standard widescreen ratio used by most TVs, monitors, and video. 16:10 (1.6) is slightly taller and was common on older laptop and monitor displays.
What ratio is a standard photo print?
A classic 4×6 inch photo print is a 3:2 ratio, while an 8×10 inch print is 4:5. Common digital camera sensors shoot at 3:2 or 4:3 depending on the manufacturer.
Can I use this for responsive web design?
Yes — the simplified ratio (e.g. 16:9) maps directly to the CSS aspect-ratio property: aspect-ratio: 16 / 9; keeps an element's proportions consistent at any size.