Aspect Ratio Calculator & CSS Generator - TikTok/Reels 9:16

Calculate aspect ratios and missing dimensions fast. Runs locally—no uploads. Includes TikTok/Reels 9:16 presets and CSS aspect-ratio snippets. Calculate now.

:
16:9
1920px
1080px
 
 
 
 
 
How to Use
 
    

  1. Pick a preset (9:16, 16:9, 4:5) or enter a custom ratio.
    2. 

  2. Enter either width or height.
    3. 

  3. Get the missing dimension instantly with a live preview.
    4. 

  4. Copy the generated CSS aspect-ratio code for your layout.
    5. 



 
 
 
Core Features
 
    

  • TikTok/Reels (9:16): Use vertical presets to validate social video dimensions quickly.
    • 

  • Generate CSS aspect-ratio: Generate modern aspect-ratio CSS snippets instantly.
    • 

  • Calculate Missing Dimension: Compute width or height automatically while keeping the ratio.
    • 

  • Visual Preview: Preview the ratio in a responsive rectangle in real time.
    • 

  • Keep it private: Everything runs locally in your browser.
    • 



 
 
 
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Calculation Logic
 
    

  • Formula:
[
H = W \times \frac{r_H}{r_W}
]
or
[
W = H \times \frac{r_W}{r_H}
]
    • 

  • CSS example:
[
\text{aspect-ratio}: \frac{16}{9}
]
    • 



 
 
 
FAQ
 
What is the aspect ratio for TikTok and Reels?


The standard is 9:16 (vertical). A common resolution is 1080×1920. Use the 9:16 preset to verify your dimensions.


How to use aspect-ratio in CSS?


Use aspect-ratio: 16/9;. We generate the snippet and helpful fallbacks for your layout.


Is my data safe (local/privacy)?


Yes. Calculations are local-only with no uploads or server storage.


Is it free? Can I use it for work?


It’s free and works well for creators and teams aligning video and UI dimensions.


Why do I see 1–2 pixel differences?


Some dimensions require rounding to whole pixels. We round to the nearest integer while preserving the ratio as closely as possible.