Aspect Ratio Calculator — Free Tool
Calculate proportional image dimensions without uploading a single file. Enter a width and height, then specify a new value for either dimension and the calculator instantly computes the other to preserve the original aspect ratio. Perfect for scaling graphics, planning layouts, and preparing images for specific display requirements.
Calculate proportional dimensions
- Aspect ratio
- 16:9
- Calculated output
- 800 × 450
Why use this tool?
Maintaining the correct aspect ratio prevents images from appearing stretched or squished when resized. This calculator does the math for you, ensuring proportional scaling every time. Enter your current width and height, change one dimension to your target value, and the tool computes the matching value automatically. No image upload is involved and no data is transmitted anywhere. The entire calculation runs in your browser using simple arithmetic, making it fast, private, and available even without an internet connection.
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Frequently asked questions
How does the aspect ratio calculator work?
Enter your original width and height to establish the ratio. Then change either the width or the height to a new value and the calculator instantly computes the corresponding dimension that maintains the same proportion.
Does this tool upload anything?
No. The aspect ratio calculator runs entirely in your browser with no server requests. There is nothing to upload and no data leaves your device.
Can I use this for video dimensions too?
Yes. Aspect ratio math applies equally to images and video. Enter the current resolution of your video and scale it to a new width or height while keeping the same proportions, such as converting from 1920x1080 to a smaller frame.
What common aspect ratios does this support?
The calculator works with any ratio you provide. Common examples include 16:9 for widescreen video, 4:3 for classic displays, 1:1 for square social media posts, and 3:2 for standard photography.
Does it handle non-standard or fractional dimensions?
Absolutely. You can enter any numeric values including decimals. The calculator preserves the exact ratio regardless of whether the dimensions are standard or custom, rounding results to the nearest whole pixel when appropriate.