Aspect Ratio Calculator

Pick a common ratio like 16:9 or 4:3 (or enter your own), type a width or a height, and get the matching other dimension instantly — perfect for images, video and design.

All calculations run locally in your browser.

How to use Aspect Ratio Calculator

  1. Choose a preset ratio or enter your own (for example 16:9).
  2. Type a width or a height in pixels.
  3. The matching dimension is calculated instantly.
  4. Copy the result or use the quick reference of common resolutions.

About this tool

An aspect ratio describes the proportion between width and height. Keeping it constant is what stops images and videos from looking stretched when you resize them.

The calculator solves the proportion for you: with ratio w:h and a known width W, the height is W × h ÷ w. A small reference table shows the standard resolutions for the selected ratio.

When to use it: resizing video, images and designs without stretching them.

Frequently asked questions

Which ratio should I use for YouTube?
16:9 is the standard for YouTube and most video platforms — for example 1920×1080 or 1280×720.
What about photos and old TVs?
Classic photos and old television use 4:3 or 3:2; square social posts use 1:1.
Why is 16:9 everywhere?
It became the standard for TVs, monitors and phones, so video platforms, presentations and slides default to it.
Is 9:16 just 16:9 rotated?
Yes — it is the portrait version used by vertical video, stories and shorts.
Which ratio should I use for printing photos?
Photo paper is commonly 3:2 or 4:3 (a 6×4-inch print is 3:2), so crop to the matching ratio before printing to avoid surprise trimming.
Does the ratio affect file size?
Not directly — size depends on total pixel count. Two images with the same number of pixels weigh about the same regardless of ratio.

Related tools

Image Resizer Resize images to exact pixel dimensions or by percentage, online and free. Unit Converter Convert units of length, weight, temperature, area, volume and more. Percentage Calculator Calculate percentages — X% of a number, percentage change, and more.

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How to use Aspect Ratio Calculator

Enter the required values into the Aspect Ratio Calculator fields. The calculation updates as you adjust inputs. Use the result for planning, comparison, or documentation.

Practical benefits

Frequently asked questions

Is this tool free to use?
Yes. Aspect Ratio Calculator is fully free with no account or subscription required.
Does it upload my files?
No. All processing occurs locally within your browser session.
Can I use this for professional projects?
Yes, the tool is designed for both casual and professional use. Always verify critical outputs.