Photography & Video
Aspect Ratio Calculator
Calculate output dimensions when resizing photos or videos to any aspect ratio.
Maintaining aspect ratio prevents distortion when resizing images or video. Whether you're preparing content for social media, print, or video editing, this calculator finds the correct dimensions in seconds.
Output Dimensions
1920 × 3413 px
- ratio
- 9:16
- megapixels
- 6.55 MP
- portrait
- Portrait orientation
Formula and method
New Height = Width × (Ratio H / Ratio W)
Maintains input width and solves for height. For standard ratios: 16:9 (widescreen), 9:16 (portrait/Reels), 1:1 (square), 4:3 (traditional), 4:5 (Instagram portrait).
Worked examples
Crop 4K for Instagram Story
- Original Width (px):
- 3840
- Target Ratio Width:
- 9
- Target Ratio Height:
- 16
Output Dimensions: 3840 × 6827 px
Resize for YouTube thumbnail
- Original Width (px):
- 1280
- Target Ratio Width:
- 16
- Target Ratio Height:
- 9
Output Dimensions: 1280 × 720 px
Assumptions and limits
- Maintains original width, solves for height
This tool provides an educational estimate. Rules, rates and personal circumstances can change the answer. Review the assumptions before relying on a result. Report a correction.
Common mistakes to avoid
- Upscaling beyond the source resolution — you cannot add pixels that don't exist.
- Mixing up ratio width:height order — 16:9 means 16 wide by 9 tall (landscape).
Frequently asked questions
What aspect ratios do social platforms use?
Instagram posts: 1:1 or 4:5 (portrait). Stories/Reels: 9:16. Facebook posts: 1.91:1 or 1:1. YouTube thumbnails: 16:9. TikTok: 9:16. Twitter/X: 16:9 or 1:1.