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Aspect ratio calculator.

Calculate aspect ratios, resize dimensions while preserving proportions, and convert between common video and image ratios. Free, instant browser tool.

Runs entirely in your browser — nothing uploaded to servers

Aspect Ratio Calculator

Enter dimensions or pick a preset to get started.

Common Presets
Original Dimensions
×
ASPECT RATIO
16 : 9
DECIMAL
1.7778
16 : 9
Resize — Locked to This Ratio
New Width
×
New Height

What is aspect ratio?

Aspect ratio is the proportional relationship between the width and height of an image, video, or screen. It is expressed as width:height — for example, 16:9 means the image is 16 units wide for every 9 units tall.

Aspect ratio is independent of actual pixel dimensions. A 1920×1080 image and a 1280×720 image both have a 16:9 aspect ratio because their width-to-height proportions are the same.

Common aspect ratios and their uses

16:9
HD video, YouTube, monitors, presentations
4:3
Classic TV, older monitors, iPad display
1:1
Instagram square, profile photos, album art
9:16
Vertical video, Instagram Reels, TikTok, Stories
3:2
DSLR photography, most camera sensors
4:5
Instagram portrait feed posts
21:9
Ultrawide cinema monitors, cinematic film
1.91:1
Open Graph / Twitter social preview images

Why aspect ratio matters

Using the wrong aspect ratio can cause images and videos to appear cropped, letterboxed, or stretched. Social media platforms enforce specific ratios for different placement types. Understanding aspect ratio helps you resize images correctly without distorting the subject or losing important parts of the frame.

Frequently asked questions

What does aspect ratio mean for video?

For video, aspect ratio determines the shape of the frame. 16:9 is the standard for most modern monitors and TV screens. 9:16 is used for vertical mobile content like Reels and Stories. Using the wrong ratio will cause black bars (letterbox/pillarbox) or cropping on the platform.

How do I resize an image without changing the ratio?

Enter the original dimensions, then fill in either the new width or new height. This calculator will automatically compute the other dimension to preserve the original aspect ratio. Use the Image Resizer tool to apply the resulting dimensions to your actual image file.

What aspect ratio should I use for social media?

It depends on the placement: 1:1 or 4:5 for Instagram feed, 9:16 for Stories and Reels, 16:9 for YouTube thumbnails and video, and 1.91:1 for link preview images. Always check each platform's latest guidelines as requirements can change.

What is the difference between 16:9 and 1920×1080?

16:9 is the ratio — the proportional relationship. 1920×1080 is a specific resolution at that ratio. Both describe the same shape, but 1920×1080 also tells you the exact number of pixels, while 16:9 only tells you the proportion.

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FAMEORBIT GUIDE · IMAGES

Aspect Ratio Calculator: complete online guide

Quick answer: calculate the aspect ratio of a width and height and resize while maintaining proportions. Prevents stretching and cropping errors by computing correct proportional dimensions.

This free browser tool is built for designers, video editors, photographers, developers and social media creators. It is designed to give you the useful result first, while the guide below explains the underlying idea, practical workflow and common mistakes. You can use FameOrbit from a modern phone, tablet or desktop browser, making the same workflow available to users and teams worldwide.

What is the aspect ratio calculator?

Aspect Ratio Calculator is a focused utility for a specific digital task. The important part is not only producing an output but understanding what that output represents and whether it matches the requirements of the next step. For professional, academic or production work, keep your source data, check units and constraints, and verify the final result after it reaches its destination.

How to use it

  1. Enter the original width and height or choose a common preset.
  2. Read the simplified aspect ratio and decimal value.
  3. Enter a new width or height to get the proportional opposite dimension.
  4. Use the result when resizing images or configuring video exports.

Practical examples

Example

A 1920×1080 image has a 16:9 aspect ratio. Resizing to 1280 width gives a height of 720.

Example

A 1080×1350 Instagram portrait has a 4:5 ratio.

Best practices and common mistakes

Start with the actual requirement instead of choosing a number, format or setting just because it is a common default. Confirm the units used by your destination, avoid unnecessary conversions, and inspect the output before publishing, printing, importing or sharing it. When the task involves private information, review the privacy and security implications before submitting sensitive content to any online service.

Frequently asked questions

What is aspect ratio?

Aspect ratio is the proportional relationship between width and height, expressed as width:height such as 16:9 or 4:3.

Why does aspect ratio matter?

Using the wrong ratio causes images and video to appear stretched, cropped or letterboxed on their destination platform.

What aspect ratio should I use for social media?

Common choices are 1:1 for square posts, 9:16 for Reels and Stories, 16:9 for YouTube, and 4:5 for Instagram portrait feed posts.

Related tools

FameOrbit focuses on practical browser utilities for images, documents, developer workflows, text and everyday tasks. The tools are free to use; for high-stakes decisions or production systems, independently verify important results.