Aspect Ratio Calculator – Find and Scale Ratios
Enter a width and height to find the simplified aspect ratio, or enter a ratio and one dimension to calculate the other. Perfect for video, design, and screen resolution work.
How to Use
- 1
Choose 'Find Ratio' to get the ratio from a width and height, or 'Scale' to calculate a new dimension
- 2
Enter your dimensions in the input fields
- 3
See the simplified aspect ratio or the scaled dimension instantly
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio describes the proportional relationship between width and height. For example, 16:9 means the width is 16 units for every 9 units of height.
What is the aspect ratio of 1920×1080?
1920×1080 has a 16:9 aspect ratio. This is the standard widescreen format used for HD and Full HD video.
How do I scale dimensions while keeping the ratio?
Switch to 'Scale Dimensions', enter your aspect ratio, then enter either the new width or height. The other dimension is calculated automatically.
Does this work for any numbers?
Yes. Enter any positive integers for width and height. The calculator simplifies the ratio using the greatest common divisor.
Keep proportions correct
An aspect ratio calculator works out the missing width or height that keeps an image or video at the same proportions. Enter the original ratio and one new dimension, and it gives you the other so nothing looks stretched or squashed.
It takes the guesswork out of resizing media.
Where aspect ratio matters
- Resizing images and videos without distortion.
- Designing for 16:9, 4:3, 1:1 and other common ratios.
- Planning layouts, thumbnails and ad sizes.
- For unit-based resizing see the pixel converter or unit converter.
Maths without an upload
The maths runs in your browser and updates as you type.