Work out the missing width, height or crop size for any social media aspect ratio.
This tool works out the simplified aspect ratio of any width and height you enter, and can also calculate a missing width or height to match a specific social media ratio like square, portrait, story or landscape, which is useful when planning a crop or a design before you open an image editor.
Knowing the exact target dimensions before you shoot, design or crop a photo means you avoid an awkward crop after the fact. If you know you need a 4:5 portrait post and you're designing a graphic from scratch, this tool tells you exactly what height to use for any given width.
Enter a width and height to see their simplified ratio (useful for checking what ratio an existing photo already is), or enter just one dimension plus a target ratio from the dropdown to calculate the matching missing dimension. If you enter both dimensions and a target ratio, the tool tells you whether your image already matches that ratio exactly.
Square (1:1) suits a classic Instagram grid post, 4:5 portrait gives you the most vertical feed space, 9:16 covers stories and reels, 16:9 is standard for YouTube and most widescreen video, and 2:3 is commonly used for Pinterest pins.
Aspect Ratio Calculator is built for creators, social media managers, small business owners and marketers who need a quick, reliable way to handle one specific job: work out the missing width, height or crop size for any social media aspect ratio. Instead of digging through a bloated all-in-one dashboard or installing a browser extension, you get a single focused page that does exactly this one thing well, works the same way on desktop and mobile, and keeps your inputs on your own device rather than sending them anywhere else. If this is a task you find yourself repeating every week, bookmark this page so it's one click away next time you need it.
Whatever this tool hands you — text, an image, a calculated number, or a piece of code — treat it as a strong first draft rather than a final answer. Skim the result against the specific post, account or campaign you're working on, adjust anything that doesn't quite match your usual voice or brand, and only then copy it into the platform you're actually posting to. Because everything here runs locally in your browser, you can safely try several combinations of inputs back to back without worrying about rate limits, accounts, or data being logged anywhere — refresh the page any time to start over with a clean slate.
It's your width and height reduced to their smallest whole-number equivalent — for example, 1920 x 1080 simplifies to 16:9, the same shape just described with smaller numbers.
Yes, enter both your image's width and height, choose the target ratio from the dropdown, and the tool will tell you whether it matches or what height it expected instead.
No, this tool only performs the math. To actually crop or resize a photo to a specific size, use the Social Media Image Resizer tool on this site.
Pixel dimensions are always rounded to the nearest whole number in the result, since a fraction of a pixel isn't meaningful for image dimensions.