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Design Utility

Aspect Ratio Calculator

Use this image ratio calculator to simplify dimensions, resize without distortion, and compare common ratios for design, print, and social media.

By ArtistTool TeamLast updated June 2026

Aspect Ratio Calculator

Enter image width and height to get a simplified ratio, then resize while preserving proportions.

Simplified Ratio

16:9

Resize From Width

1200 x 675

Resize From Height

-

Common Ratios Cheat Sheet

1:1

Square social posts, avatars

4:5

Portrait posts and print layouts

3:2

Photography and posters

16:9

Video, presentations, widescreen

21:9

Ultra-wide media and banners

How to use Aspect Ratio Calculator

To simplify a ratio, enter your image's width and height in the fields above — the tool divides both by their greatest common divisor and shows the reduced ratio (for example, 1920 × 1080 becomes 16:9). Use this when you need to confirm that a file matches a platform requirement or print format.

To resize without distortion, enter a target width (or height) in the scale section and the tool calculates the matching dimension automatically. Copy those values into your image editor's resize dialog and make sure "Constrain proportions" is off — you are entering exact pixel values, not a percentage.

A common mistake is resizing by entering only one dimension while the editor scales the other automatically — that approach is fine only if your editor is already locked to the correct ratio. If you have cropped or rotated the image since it was created, verify the current ratio first before scaling, because the starting ratio may have changed.

Common Image Ratios

RatioTypical Use
1:1Square social posts, avatars
4:5Portrait posts and print layouts
3:2Photography and posters
16:9Video, presentations, widescreen
21:9Ultra-wide media and banners

Worked examples

Example 1: Resizing a 1920×1080 video frame to 1280 wide

  1. Original dimensions: 1920 × 1080 pixels (16:9 ratio)
  2. Target width: 1280 pixels
  3. Scale factor: 1280 ÷ 1920 = 0.6667
  4. New height: 1080 × 0.6667 = 720 pixels

Result: 1920×1080 resized to 1280×720 — ratio preserved at 16:9

Example 2: Checking if 1080×1350 is a valid Instagram portrait

  1. Image dimensions: 1080 × 1350 pixels
  2. GCD of 1080 and 1350 = 270
  3. Simplified ratio: 1080 ÷ 270 : 1350 ÷ 270 = 4:5

Result: 1080×1350 px = 4:5 ratio — correct for portrait Instagram posts

Example 3: Finding the height for a 16:9 banner at 728 pixels wide

  1. Target ratio: 16:9
  2. Target width: 728 pixels
  3. Height: (728 ÷ 16) × 9 = 45.5 × 9 = 409.5 pixels
  4. Round to nearest whole pixel: 410 pixels

Result: 728×410 pixels — closest 16:9 banner at 728px wide

FAQ: Aspect Ratio Questions

What is the most common aspect ratio for websites?

16:9 is the standard for video and widescreen displays. For web content, 16:9 or 4:3 are common. For social media, aspect ratios vary by platform—1:1 for Instagram posts, 9:16 for stories.

How do I keep aspect ratio when resizing?

Use the formula: (New Width ÷ Original Width) × Original Height = New Height. Or better yet, use this calculator to do it instantly.

What ratio should I use for Instagram?

For square feed posts: 1:1. For portrait feed posts: 4:5. For Stories and Reels: 9:16. Always check the platform's current specs, as they occasionally update.

What happens if I don't maintain aspect ratio?

Your image stretches or squishes. A portrait photo stretched to wide ends up looking distorted and unprofessional. Always maintain the original ratio unless intentionally cropping.

Should I match print paper size to aspect ratio?

Yes. A4 paper is roughly 4:5 aspect ratio, while 8x10 prints are 4:5. Matching aspect ratio prevents unwanted cropping. Use our paper size chart to find the right dimensions.

Learn More & Related Tools

Read our comprehensive aspect ratio guide to master ratios for any screen and design.

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