About this tool
Enter a width and height to get the simplified aspect ratio, or lock a ratio and enter one dimension to compute the other — the everyday task when resizing images and video without distortion. Common presets (16:9, 4:3, 3:2, 1:1, 9:16) are one click away.
16:9 won the format wars and now rules TVs, monitors and YouTube; 9:16 is its vertical mirror for Reels, Shorts and TikTok; photography still leans on 3:2 (from 35mm film) and 4:3 (from micro four-thirds and older sensors). Getting the ratio wrong means letterboxing, cropping or the unmistakable squash of a stretched image.
How to use it
- Enter your original width and height to see the simplified ratio.
- To resize, type the new width (or height) — the other dimension is calculated to preserve the ratio.
- Use the presets for standard video and social formats.
Frequently asked questions
How is an aspect ratio simplified?
Divide both dimensions by their greatest common divisor: 1920 × 1080 ÷ 120 = 16:9.
What resolution is 16:9?
Any pair in that proportion: 1280×720 (HD), 1920×1080 (Full HD), 2560×1440 (QHD), 3840×2160 (4K UHD).
What ratio should social media videos use?
Vertical 9:16 for Reels, Shorts and TikTok; 1:1 or 4:5 for feed posts; 16:9 for YouTube and landscape embeds.