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Kordu Tools
Image Tools Runs in browser Updated 08 Apr 2026

Aspect Ratio Calculator

Find the aspect ratio of any image, or resize dimensions while keeping the ratio locked.

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Common aspect ratios
RatioUse case
1:1Instagram square, profile pictures
4:3Traditional TV, iPad, PowerPoint
3:2DSLR photos, 35mm film
16:9YouTube, HD/4K video, monitors
16:10MacBook, widescreen laptops
21:9Ultrawide monitors, cinema
9:16TikTok, Reels, Stories
4:5Instagram portrait
2:3Pinterest, portrait photos
3:4iPad portrait
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How to use Aspect Ratio Calculator

  1. Enter dimensions

    Type the width and height of your image or video in pixels (or any unit).

  2. See the ratio

    The simplified aspect ratio appears instantly — for example, 1920×1080 shows 16:9.

  3. Resize (optional)

    Switch to Resize mode, enter a new target width or height, and the other dimension is calculated to maintain the ratio.

  4. Use a preset

    Click 'Use' on any common ratio in the reference table to load it into resize mode.

Aspect Ratio Calculator FAQ

What is an aspect ratio?
An aspect ratio describes the proportional relationship between an image's width and height, expressed as two numbers separated by a colon (e.g. 16:9). It determines the shape of the image — wide, tall, or square.

What is the most common aspect ratio for video?
16:9 is the standard for HD and 4K video (1920×1080, 3840×2160). YouTube, Netflix, and most streaming platforms use 16:9. Vertical video (TikTok, Instagram Reels) uses 9:16.

How does the calculator simplify ratios?
It divides both width and height by their greatest common divisor (GCD). For example, 1920÷120 = 16 and 1080÷120 = 9, giving 16:9.

Can I use units other than pixels?
Yes. The calculator works with any unit as long as both dimensions use the same unit — pixels, inches, centimetres, or points.

What aspect ratio should I use for social media?
Instagram posts: 1:1 (square) or 4:5 (portrait). Instagram Stories/Reels: 9:16. YouTube: 16:9. Twitter/X: 16:9 or 2:1. Facebook: 1.91:1. Pinterest: 2:3.

How do I resize without distortion?
Use the resize mode. Enter your original dimensions and one new dimension (width or height). The calculator computes the other to preserve the ratio, preventing stretching or squashing.

Background

Calculate the aspect ratio of any image or video resolution. Enter a width and height (in pixels or any unit) and get the simplified ratio instantly — for example, 1920×1080 simplifies to 16:9, and 3024×4032 simplifies to 3:4.

In resize mode, enter the original dimensions and a new target width or height. The calculator computes the other dimension to preserve the aspect ratio exactly — no stretching or cropping. Useful for resizing images for different platforms while keeping proportions.

A built-in reference table lists common aspect ratios and where they are used: 16:9 for YouTube and HD video, 9:16 for TikTok and Stories, 4:3 for traditional TV and iPad, 1:1 for Instagram squares, 21:9 for ultrawide monitors, and more.

Who is this for: photographers, video editors, social media managers, web designers, game developers, and anyone working with image or video dimensions.

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