What is an aspect ratio?

An aspect ratio is the proportional relationship between the width and height of an image, video, or screen, written as two numbers separated by a colon (e.g. 16:9).

How do you calculate aspect ratio from resolution?

To calculate aspect ratio, find the greatest common divisor (GCD) of the width and height, then divide both numbers by the GCD. For example, 1920x1080 divided by GCD 120 simplifies to 16:9.

What is the standard widescreen aspect ratio?

The standard widescreen aspect ratio for high-definition television, computer monitors, and web videos is 16:9 (1.77:1).

How does the aspect-ratio property work in CSS?

The CSS aspect-ratio property allows you to define a target aspect ratio for a box layout, such as "aspect-ratio: 16 / 9". The browser will calculate the missing dimension automatically based on container widths, preventing layout shifts.

What is the difference between letterboxing and pillarboxing?

Letterboxing adds horizontal black bars to the top and bottom of a wide video to fit a narrower screen. Pillarboxing adds vertical black bars to the left and right of a narrow video to fit a wider screen.

Does changing aspect ratio affect image file size?

Changing the aspect ratio by cropping or stretching does not directly change file size, but resizing the dimensions (pixel count) does. Cropping an image reduces its resolution and file size.

What is the Golden Ratio and is it used in web design?

The Golden Ratio is approximately 1.618:1. It is a mathematical ratio found in nature that is believed to be aesthetically pleasing. Web designers use it to create balanced column layouts.

How do I scale an image without distortion?

To scale an image without distortion, you must maintain the original aspect ratio. Always multiply or divide both the width and height by the same scaling factor (e.g., resizing both by 50%).

What aspect ratio is best for mobile screens?

For mobile phones, vertical aspect ratios like 9:16 (the reverse of widescreen) or 4:5 are ideal, as they fill the screen when the phone is held in portrait mode.

How does a camera sensor capture different aspect ratios?

Camera sensors are physically fixed to a specific ratio (often 3:2 for DSLRs or 4:3 for smartphones). When you select a different aspect ratio in camera settings, the camera crops the sensor image to fit that target shape.

utility calculator

Aspect Ratio & Image Dimension Calculator

Calculate image dimensions, find aspect ratios, scale sizes proportionally, and preview crop dimensions.

Formula Verified by Dr. Arthur Pendelton, PhD

Inputs

Aspect Ratio Presets

Source Dimensions

Width (px)

Height (px)

Lock aspect ratio link

Calculated Aspect Ratio

16:9

1920 x 1080

Proportional Missing Dimension Solver

Enter either a new target Width OR target Height, and get the corresponding size keeping the ratio.

Target Width (px)

Solved Height (px)

720

Target Height (px)

Solved Width (px)

1280

Results

Related guides

Learn more about this calculation

Guide

Understanding Calculator Formulas: How DTC Turns Inputs into Results

Understand how Do The Calculation formulas are presented, what the explanation blocks mean, and how to verify calculator logic before using a result in a real decision.

Site Guide

How to Use Do The Calculation Calculators: A Practical Step-by-Step Guide

Learn the fastest reliable workflow for using Do The Calculation calculators, reading results, checking formulas, and using save, print, share, and export actions correctly.