Aspect ratio calculator
Free · no sign-upResize width and height while keeping the same aspect ratio.
Resize an image or video while keeping its proportions. Set the aspect ratio — like 16:9 — then enter a new width to get the matching height, or a new height to get the width. Nothing stretches or squashes. Free, no sign-up.
- ✓Keep the exact aspect ratio
- ✓Width → height and height → width
- ✓Simplified ratio (e.g. 16:9)
- ✓Any ratio and any size
- ✓Free — updates as you type
Who it's for
- Resizing images and thumbnails
- Video and screen resolutions
- Cropping to a target ratio
- Responsive design sizing
How it works
- 1Set the ratio width and height.
- 2See the simplified ratio.
- 3Enter a new width for the height.
- 4Or a new height for the width.
Frequently asked questions
What is an aspect ratio?+
The proportional relationship between width and height, written width:height — for example 16:9, 4:3 or 1:1. Keeping it fixed stops an image from stretching.
How do I resize keeping the ratio?+
Enter your ratio, then a new width — the calculator returns the height that preserves it (new height = new width × ratio height ÷ ratio width).
Is it free?+
Yes, completely free and runs in your browser.
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