Aspect Ratio Calculator
Calculate aspect ratios and resize dimensions. Get the ratio from a width and height, or find a new width or height that keeps the same ratio.
About This Free Online Aspect Ratio Calculator
Our free Aspect Ratio Calculator does two jobs. Enter a width and height and it gives you the simplified aspect ratio (for example, 1920 × 1080 becomes 16:9). Or lock a ratio and change one dimension, and it calculates the other so your image or video stays perfectly in proportion — no stretching or cropping. It is ideal for resizing photos and videos, fitting designs to screens and social formats, and planning layouts. Everything calculates instantly in your browser, with no signup and nothing uploaded.
Features of Our Aspect Ratio Calculator
- Get the simplified ratio from width × height
- Resize one dimension while keeping the ratio
- Common presets (16:9, 4:3, 1:1, 21:9)
- Instant, proportional results
- Works for any image, video, or screen
- 100% private — runs in your browser
How to Use the Aspect Ratio Calculator
The Aspect Ratio Calculator works right in your browser — no signup, no installation. Follow these steps:
- Enter your original width and height to see the aspect ratio.
- To resize, set the target ratio (or keep the detected one).
- Change the width or height and read the matching dimension.
- Use the proportional size with no stretching or cropping.
Frequently Asked Questions About Aspect Ratio Calculator
What is an aspect ratio?
It is the proportional relationship between width and height, written like 16:9. It stays the same when you scale an image or video up or down, which is what keeps it from looking stretched.
How do I resize without distortion?
Change one dimension and let the calculator set the other from the ratio. As long as both change in proportion, the image keeps its shape.
What are common aspect ratios?
16:9 for most video and screens, 4:3 for older displays, 1:1 for square social posts, and 21:9 for ultrawide. The presets fill these in for you.
Is anything uploaded?
No. The calculator works entirely in your browser — no images are uploaded and there is no signup.
Why Choose the Aspect Ratio Calculator?
The Aspect Ratio Calculator is built for answers you can rely on, not rough guesses. Every calculation happens locally in your browser the moment you enter a value, so results are immediate, the math is transparent, and nothing you type ever leaves your device.