Image Tools

Aspect Ratio Calculator

Calculate dimensions (width/height) based on aspect ratio. Find missing constraints for images and video.

Use Aspect Ratio Calculator to get instant results without uploads or sign-ups. Everything runs securely in your browser for fast, reliable output.

Your results will appear here.

Ready to run.

About this tool

Designers and video editors constantly deal with aspect ratios. Whether you are resizing an image for Instagram (1:1 or 4:5) or encoding video for YouTube (16:9), keeping the correct proportions is vital.

This tool ensures your content doesn't get stretched or squashed. It calculates the exact pixel dimensions you need based on your target ratio.

Usage examples

HD Video

1920 width, 16:9

Width: 1920, Ratio: 16:9 → Height: 1080

Cinematic

Find Width for 1080p height

Height: 1080, Ratio: 21:9 → Width: 2520

How to use

  1. Enter the known "Width" or "Height".
  2. Select a preset Aspect Ratio (e.g., 16:9) or enter a custom one.
  3. The missing dimension is calculated instantly.
  4. Use standard presets for YouTube covers, Instagram, etc.

Benefits

  • Supports common presets (16:9, 4:3, 1:1, 9:16)
  • Custom ratio support (e.g. 2.35:1)
  • Calculate Width from Height or vice-versa
  • Round to nearest integer option

FAQs

What is 16:9?

16:9 is the standard aspect ratio for widescreen TV and most online video platforms like YouTube.

How do I calculate missing width or height?

Divide the known dimension by the corresponding ratio value, then multiply by the other ratio value. For example, with 16:9 and width 1920: height = (1920/16) × 9 = 1080.

What aspect ratio should I use for Instagram?

Instagram supports multiple ratios: 1:1 (square) for feed posts, 4:5 (portrait) for feed posts, and 9:16 (vertical) for Stories and Reels.

Can I use custom aspect ratios?

Yes, select "Custom" and enter your own width and height values to calculate dimensions for any non-standard aspect ratio.

What aspect ratio should I use for Instagram?

Feed posts: 1:1 (square) or 4:5 (portrait). Stories/Reels: 9:16 (vertical). IGTV: 9:16 or 16:9. Landscape posts: 1.91:1. Profile photo: 1:1. Use 1080x1080 (1:1) for maximum engagement on feed posts.

How do I avoid black bars in videos?

Match video aspect ratio to display. Crop or scale to fit. Pillarbox (vertical bars): wide video on portrait display. Letterbox (horizontal bars): portrait on wide display. Use platform-native ratios: 16:9 (YouTube), 9:16 (TikTok), 1:1 (Instagram feed).

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