Aspect Ratio Calculator
The ratio of any resolution, and matching heights for a new width.
Reducing a resolution to a ratio
Divide both numbers by their greatest common divisor: 1920 and 1080 share 120, giving 16:9. Scaling keeps the ratio by cross-multiplying: new height = new width × h / w. Half of 1920×1080 is 960×540, not 960×500.
The ratios you'll actually meet
16:9 rules monitors, TVs and consoles (1280×720 up to 3840×2160). 21:9 ultrawides are really 43:18 or 12:5 depending on the panel. Phones run tall: 19.5:9 and stranger. 4:3 survives in retro emulation, and 3:2 in laptops. UI that assumes one ratio breaks on the rest, which is why anchors and safe areas exist.