Aspect Ratio & Resolution Calculator
Reduce aspect ratios, find missing dimensions, scale without distortion, and fit images to any frame. Free aspect ratio calculator, instant, in your browser.
What this tool does
This aspect ratio calculator handles the dimension math that platforms and layouts keep demanding: reduce a ratio to its simplest form, find a missing width or height, scale a size up or down without distortion, and convert between resolutions. It runs in the browser and needs no file.
Enter the numbers you know and the rest follows, whether you are framing a thumbnail, fitting an image into a layout, or matching an export preset.
How it works
- Choose the calculation: missing dimension, ratio reduction, scaling, or fit.
- Enter the numbers you know.
- Get the exact result instantly.
Supported formats
No file input: everything runs in your browser. Nothing is uploaded.
When to use it
Social frames
Convert a photo to the exact shape a platform wants, without stretching it.
Thumbnails and banners
Compute the height that matches a width at 16:9, or the other way around.
Fit or fill a layout
Decide between showing the whole image and filling the frame, with numbers behind the choice.
Match an export
Confirm the ratio before the render instead of discovering the bars afterwards.
Ratio math, without the spreadsheet
An aspect ratio is the relationship between width and height, and most production mistakes come from breaking it: a stretched thumbnail, a cropped face, an export with letterboxing nobody asked for. The calculator keeps that relationship intact while the numbers change around it.
Four operations cover the cases that actually come up: find a missing dimension, reduce a ratio to its simplest form, scale a size to a new one, and fit one rectangle inside another by containing or covering. Each answers a question that shows up in every project eventually.
It runs in the browser with no file and no account. Enter numbers, get numbers, back to work.
Frequently asked questions
What is an aspect ratio, in plain terms?
It is the shape of the rectangle: how many units wide for every unit tall. 16:9 is widescreen video, 1:1 is a square, 9:16 is a phone held upright. Same photo, different shapes.
Why did my image end up stretched?
The width and height were changed independently, so the ratio broke. Calculate the matching height for your new width here and the distortion disappears.
Does it work for video dimensions too?
Yes. Pixels do not care whether they end up in an image or a video frame; resolution and ratio math is identical for both.
What is the difference between fit and fill?
Fit shows the entire image inside the space and leaves bars where it falls short. Fill covers the whole space and crops whatever sticks out. The calculator shows the dimensions each approach produces.
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Privacy
Your file never leaves your device.
Platform and product names are used descriptively for reference only; LimkaKit is not affiliated with or endorsed by YouTube, Instagram, TikTok, Adobe, or Blackmagic Design.