Aspect Ratio Calculator
Aspect Ratio Calculator helps you scale images and videos while keeping proportions locked. Enter your original dimensions and one new measurement – the tool calculates the other automatically. Perfect for resizing photos for social media, web projects, or video production. Works without signup or downloads.
Enter original dimensions and either a new width or new height to calculate the locked aspect ratio. Use presets for common ratios.
New Dimensions — fill ONE field
How to use it
- Enter your original width and height values
- Input either a new width or new height (whichever you're changing)
- View the calculated dimension that maintains your aspect ratio
- Optionally click a preset ratio button (16:9, 4:3, 1:1, 9:16) to auto-fill common formats
Pro tips
- Use preset ratio buttons for standard formats – saves time if you're resizing for Instagram Stories (9:16) or YouTube thumbnails (16:9)
- Try entering your new dimension first if you have a fixed target size – the calculator works either direction
FAQ
What is aspect ratio?
Aspect ratio is the proportional relationship between width and height. A 16:9 ratio means for every 16 units wide, it's 9 units tall. Maintaining it prevents distortion.
Can I use this for video dimensions?
Yes. Enter video width and height, then specify a new width or height. The tool calculates the matching dimension for any video format.
Do my numbers need to be in pixels?
No. Use any unit – pixels, inches, centimeters. The ratio calculation works the same regardless of measurement unit.