Aspect Ratio Calculator
Solve missing width or height for a ratio.
Loading tool
Enter 16:9 and a width to get the height, or start from pixels you already have. Optional crop preview stays on this device.
How to use this tool
- Choose a file on this device. Pick an image from your computer or phone. The file stays in this browser tab.
- Set size or quality. Use the sliders and format controls. A preview is shown when the tool can make one.
- Download the new file. Save the result. The original on disk is not overwritten.
Common frames
Presets cover 1:1, 4:3, 3:2, 16:9, 9:16, and 21:9. Custom ratios accept any two positive numbers.
Privacy
If you drop a photo to preview the crop, files never leave the device. Pure number mode never reads a file.
Frequently asked
How do I get a 1200 by 630 Open Graph size?
That is about 1.91:1. Use the OG size guide if you want platform presets.
Does the calculator crop the file for me?
It can preview. Use the cropper to export pixels.
Are cinema ratios exact?
Presets use integer pixels. The last pixel may round.
Can I lock height instead of width?
Yes. Fill the known side; the other updates.
Is 4K 16:9?
UHD 3840 by 2160 is 16:9. DCI 4K is 17:9.