# Aspect Ratio Calculator

> Aspect ratio calculator: get exact width and height dimensions for 16:9 video, images, and screens from any ratio. Free, private, runs in your browser.

- **Canonical URL:** https://boringtoolskit.com/aspect-ratio-calculator/
- **Category:** Everyday Calculators
- **Evidence level:** authored-methodology
- **Reviewed:** July 26, 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Reduce width and height by their greatest common divisor; the ratio is width : height and the decimal value is width / height.

## Worked example

1920 x 1080 reduces by GCD 120 to 16:9, or 1.778.

## Common questions

### What is an aspect ratio calculator and how does it work?

An aspect ratio calculator is a browser-based tool that computes the proportional relationship between the width and height of an image, screen, or design. Enter any two values (width and height, or one value plus a target ratio), and the calculator instantly returns the missing dimension or simplifies the ratio to its standard form.

### Do I need to create an account or sign up to use this aspect ratio calculator?

No. This aspect ratio calculator is completely free, requires no signup, and runs entirely in your browser. Your data is never sent to a server or stored anywhere ,  everything is processed locally on your device for full privacy.

### Can this aspect ratio calculator handle custom ratios for video, print, and web design?

Yes. The aspect ratio calculator supports standard ratios like 16:9, 4:3, and 21:9, as well as any custom ratio you enter. Simply input your desired width-to-height proportion, and it will calculate the corresponding dimensions for your specific use case.

## Sources

- [Calculation methodology](/methodology/)
- [Quality evidence and verification standard](/quality-evidence/)

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