Aspect Ratio Calculator
Pick a standard ratio and solve the missing side, or type any two numbers and see the exact ratio plus the closest standard name. No image needed — just the numbers.
Enter your base dimensions, then type either a new width or a new height — the other side is calculated to keep the same ratio.
How does it work?
Leave the preset on Custom and type any width and height — you'll see the exact simplified ratio and the closest named standard, handy for figuring out "what ratio is this weird export, anyway?" Pick a real preset instead and the calculator locks that ratio: change one field and the other updates automatically, so you always land on a clean size.
What does "closest standard" mean?
Real-world dimensions are rarely a perfectly clean ratio — a 1917×1080 export is "almost" 16:9 but not exactly. The calculator compares your numbers against a list of common photo, video and print ratios and shows the nearest match with the percentage difference, so you know how far off (if at all) you are.
Which ratios are in the "standard" list?
Square (1:1), classic photo/video (4:3, 3:2, 5:4), widescreen and cinema (16:9, 16:10, 1.85:1, 21:9, 2.39:1), social portrait formats (4:5, 3:4, 2:3, 9:16), the ISO paper ratio (√2:1, used by A4/A3/A5…) and the golden ratio (1.618:1).
☕ The robot runs on caffeine
This tool is free and always will be. If it saved you time, a coffee keeps the robot scary.