Aspect Ratio Calculator
Aspect Ratio Calculator is a free online calculator that helps you compute aspect ratios and resize dimensions while preserving the original proportion; 16:9, 4:3, 21:9 and more. Aspect Ratio Calculator uses 5 input fields, returns 4 output values, and runs in your browser on the device.
Key facts
- Inputs
- 5 fields: Mode, Original width (px), Original height (px), New width (px) — leave 0 to derive from new height, and New height (px) — leave 0 to derive from new width
- Outputs
- 4 values: Width, Height, Aspect ratio, and Decimal ratio
- Runtime
- your browser on the device
- Mode
- Calculator
- Privacy
- Files and text stay in the browser session.
- Cost
- $0, no account required
How to use Aspect Ratio Calculator
- 1
Paste or fill in the input
Enter your text or values into the input fields on the page.
- 2
Run the utility
Click Compute to run the utility in your browser and review the result.
- 3
Copy the output
Copy the output value you need from the result panel.
Aspect Ratio Calculator details
First, enter Mode in Aspect Ratio Calculator. Next, review Width, Height, Aspect ratio, and Decimal ratio. Additionally, Aspect Ratio Calculator uses 5 input fields and 4 output blocks so the result is easy to scan and copy.
Two modes. Mode 1; resize while keeping ratio: enter the original width and height plus one new dimension, get the matching dimension that preserves the aspect ratio. Mode 2; find ratio from dimensions: enter any width and height, get the simplified ratio (e.g. 1920×1080 → 16:9) plus the decimal value. Useful for video aspect ratios (16:9, 21:9), social-media images (1:1, 4:5, 9:16 for Reels/TikTok/Stories), monitor and TV sizing, and responsive design breakpoints. Runs locally in your browser.
Common searches
- aspect ratio calculator
- ratio calculator
- resize while keeping ratio
- 16:9 calculator
- 21:9 calculator
- screen aspect ratio calculator
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Frequently asked
What is Aspect Ratio Calculator?
Aspect Ratio Calculator is a free online calculator that helps you compute aspect ratios and resize dimensions while preserving the original proportion; 16:9, 4:3, 21:9 and more. Aspect Ratio Calculator uses 5 input fields, returns 4 output values, and runs in your browser on the device.
What inputs and outputs does Aspect Ratio Calculator use?
Aspect Ratio Calculator uses 5 input fields: Mode, Original width (px), Original height (px), New width (px) ; leave 0 to derive from new height, and New height (px) ; leave 0 to derive from new width. Aspect Ratio Calculator returns 4 output values: Width, Height, Aspect ratio, and Decimal ratio.
Do my files and data stay private?
Yes. Aspect Ratio Calculator runs entirely in your browser using your device's CPU. Files and text are never uploaded to our servers, so your data stays private.
How do I use Aspect Ratio Calculator?
Open Aspect Ratio Calculator, paste or fill in the input fields, and the result updates instantly. Aspect Ratio Calculator runs in your browser with no upload and no waiting.
Which browsers does Aspect Ratio Calculator support?
Any modern browser works in Chrome, Firefox, Safari, and Edge on desktop and mobile. Aspect Ratio Calculator uses standard web APIs and does not require any plugin, extension, or sign-up.