Image Ratio Calculator

Professional tool for calculating image aspect ratios and dimensions. Maintain proportions when resizing photos and videos with preset ratios for social media, web design, and print.

Ratio Calculator
Resize by Ratio
Common Ratios

Original Dimensions

Calculated Aspect Ratio

Enter original dimensions and click "Calculate Ratio" to see the aspect ratio.

Set Target Dimensions

Calculated Result

Select a preset ratio or enter custom dimensions to calculate the resized dimensions.

Common Aspect Ratios Reference

Ratio Common Use Example Resolutions Decimal
16:9 HD Video, YouTube, Widescreen 1920×1080, 1280×720, 3840×2160 1.778
9:16 Vertical Video, TikTok, Stories 1080×1920, 720×1280 0.563
4:3 Standard TV, Old Monitors, iPad 1024×768, 800×600, 640×480 1.333
3:2 DSLR Cameras, Photo Prints 3000×2000, 1800×1200 1.500
1:1 Square, Instagram Posts 1080×1080, 1200×1200 1.000
21:9 Ultrawide Monitor, Cinema 2560×1080, 3440×1440 2.333
5:4 Old Monitors, Large Format 1280×1024, 2560×2048 1.250
2:3 Portrait Photos, Posters 2000×3000, 1200×1800 0.667
3:4 Tablet Portrait, Books 1536×2048, 768×1024 0.750
4:5 Instagram Portrait 1080×1350, 1200×1500 0.800

Platform-Specific Recommendations

  • YouTube: 16:9 (1920×1080 recommended)
  • Instagram Feed: 1:1 (1080×1080) or 4:5 (1080×1350)
  • Instagram Stories: 9:16 (1080×1920)
  • TikTok: 9:16 (1080×1920)
  • Facebook Cover: 16:9 (820×462)
  • Twitter Header: 3:1 (1500×500)
  • LinkedIn Banner: 4:1 (1584×396)
  • Pinterest Pin: 2:3 (1000×1500)
Instant results No signup required Standard formulas Free to use

Frequently Asked Questions about Image Ratio Calculator

How do I calculate the aspect ratio of an image without uploading it?

Just type the width and height in pixels into the Ratio Calculator tab. The tool processes the numbers locally in your browser – no file upload is needed. You’ll get the simplified ratio, decimal value, and percentage in less than a second.

What are the most common aspect ratios for Instagram and TikTok?

Instagram feed posts work best at 1:1 (square) or 4:5 (portrait). Instagram Stories and TikTok both use 9:16. The Common Ratios tab in this calculator lists all the standard platform specs so you don’t have to memorize them.

Can I use this image ratio calculator on my phone or tablet?

Absolutely. The tool is fully responsive and works in mobile browsers without any app download. I’ve used it on an iPhone and an iPad to check dimensions while on the go – the touch inputs are smooth and the tabs are easy to tap.

Is it really free? Are there any hidden limits?

Yes, it’s completely free with no sign‑up, no watermarks, and no daily usage caps. The only “ads” are standard display banners that support the site, and they don’t interfere with the calculator. You can calculate and resize as many images as you need.

Why should I trust an online image ratio calculator with my work?

Because this tool never uploads your images. All the math runs in your web browser using JavaScript. Your original files stay on your computer, and the numbers you enter are never sent to a server. This makes it safe for confidential client projects, medical images, or any private content.

Which preset ratios should I use for YouTube thumbnails?

YouTube recommends 16:9 for both videos and thumbnails. The most common thumbnail resolution is 1280×720. In the Resize by Ratio tab, select the 16:9 preset, lock the width at 1280, and the tool gives you the exact height of 720.