Aspect Ratio Calculator
Enter a width or height and get the matching dimension for any aspect ratio, from 16:9 video frames to 1:1 social posts. Includes common presets and a visual preview of the resulting shape.
Using the Aspect Ratio Calculator: step by step
- Pick a ratio preset or enter a custom width:height pair.
- Type the dimension you know, either width or height.
- The missing dimension is calculated instantly.
- Check the visual preview to confirm the shape fits your layout.
What people use the Aspect Ratio Calculator for
- Resizing video frames and thumbnails without distortion.
- Preparing correctly proportioned images for social platforms.
- Checking whether a photo can crop cleanly to a cover or banner slot.
- Converting design specs between ratios during handoff.
Inside the Aspect Ratio Calculator
The calculation preserves the ratio by cross-multiplying: width times ratio height equals height times ratio width, so a 16:9 frame at 1920 wide must be 1080 tall. Presets cover the ratios you meet daily, 16:9 and 4:3 for screens, 1:1 and 9:16 for social formats, and 21:9 for ultrawide. The math runs instantly in your browser.
Limitations worth knowing
The calculator preserves geometric proportion only; pixel dimensions you enter should also match the resolution requirements of the platform you target.
Aspect Ratio Calculator FAQ
How do I choose which dimension to enter?
Enter whichever side is fixed by your layout, and the calculator solves for the other.
What does 16:9 actually mean?
Sixteen units of width for every nine of height, the standard widescreen shape for video and monitors.
Can I use it for print ratios?
Yes, enter any custom ratio such as 8.5:11 for letter-size prints.
Last reviewed: October 2026.