What is an aspect ratio?

An aspect ratio describes the proportional relationship between an image's width and height, expressed as W:H (e.g. 16:9). It stays the same regardless of the actual pixel size.

How is the simplified ratio calculated?

The calculator divides both the width and height by their greatest common divisor (GCD). For example, 1920x1080 simplifies to 16:9 because GCD(1920, 1080) = 120.

Can I solve for width if I only know the height?

Yes. Enter your original width and height, then type only the new height. The calculator will compute the new width automatically.

What are the most common aspect ratios?

The most common are 16:9 (widescreen HD/4K video), 4:3 (older monitors and cameras), 1:1 (square, used on Instagram), and 9:16 (portrait video for mobile).

Does this tool modify my image file?

No. This is a pure calculation tool. It only computes numbers — no image file is uploaded or modified.

Aspect Ratio Calculator

Name: Aspect Ratio Calculator
Availability: InStock
Author: Nham Vu

Enter any two known values (width, height, or ratio) to instantly calculate the missing dimension and see the simplified ratio.

Original Dimensions

Width (px)

Height (px)

Common Presets

Scale To

Enter one value — the other is calculated automatically.

New Width (px)

New Height (px)

Enter width and height to calculate the aspect ratio

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Summary

Enter any two known values (width, height, or ratio) to instantly calculate the missing dimension and see the simplified ratio.

How it works

Enter the original width and height of your image.
Type a new width or new height in the "Scale" section.
The calculator fills in the missing dimension to preserve the ratio.
The simplified ratio (e.g. 16:9) is shown automatically.
Use the preset buttons for common ratios like 16:9, 4:3, or 1:1.

Use cases

Resize a photo without distorting it.
Scale banner or ad creatives to different sizes.
Find the simplified ratio of any custom resolution.
Check whether two images share the same aspect ratio.
Calculate canvas dimensions for video or UI design.
Convert between common display resolutions proportionally.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu