Ratio Calculator
Simplify a ratio and find the missing number in A:B = C:D.
Works in your browser. Nothing you type or open is sent to us.
Pixels, inches, centimetres or a ratio such as 16 and 9: any unit works, as long as both are the same.
Resize, keeping the ratio
Type either one and the other is worked out.
Print sizes for this ratio
How much of the picture each print size cuts off when the picture fills the paper. 0% means it fits exactly.
| Ratio | Cut off |
|---|
Ratio Calculator at a glance
- Price
- Free
- Data sent to us
- None, it runs in your browser
- Sign-up
- Not needed
- Takes
- Width and height in any unit, or a picture
- Gives
- Ratio, decimal, new size at the same ratio
- Also
- Crop for 12 print sizes
How to use Ratio Calculator
- Type the sizeType the width and height, tap a common ratio, or read the size from a picture.
- Read the ratioThe ratio appears reduced to whole numbers, with the nearest common ratio and its use.
- Resize or printType a new width or height to get the other, and check how each print size crops.
The calculator is set to 3:4 with a new first number of 15, so the missing number is 15 × 4 ÷ 3 = 20, and 3:4 = 15:20. Type any two numbers to simplify them: 18:24 reduces to 3:4, and 8.5:11 to 17:22. Type a new first or second number below to scale the ratio.
How it works
Ratio Calculator is a web page that does its work on your own device. The file you choose is opened by your browser, changed there and saved from there; it is never sent to a server, so there is no copy of it anywhere to delete, no queue and no waiting for an upload. Most online tools of this kind send your file to their servers and work on it there, and many keep it for a while. This one does not. There is no account, no watermark and no limit on how often you use it, and the result downloads the moment it is ready.
Scaling a recipe or a mix
A 2:3 mix with 500 of the first part needs 750 of the second. Put 2 and 3 above, 500 as the new width, and read the new height.
Other shortcuts
Aspect Ratio Calculator · 16:9 Calculator
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