Whether you’re a designer, developer, photographer, or social-media creator, keeping the correct aspect ratio is critical. Stretching or squashing an image looks unprofessional and can hurt engagement. Our Aspect Ratio Resizer is a lightning-fast, 100 % free online tool that instantly calculates the missing width or height while preserving the exact ratio you need.
Key Benefits
Zero Guesswork: Enter one dimension and the tool computes the other in real time.
Universal Presets: One-click ratios for HD video (16:9), Instagram square (1:1), stories (9:16), ultrawide monitors (21:9) and more.
Custom Ratios: Type any ratio—great for print sizes, packaging, animations or unusual screen layouts.
Ultra-Responsive: Works perfectly on phones, tablets, laptops and desktops. No app download required.
One-Tap Copy: Copy the final dimensions to your clipboard for pasting into Photoshop, Figma, CSS or any editor.
Privacy First: No data leaves your browser; everything runs locally and instantly.
Typical Use-Cases
Resizing YouTube thumbnails without distortion.
Creating consistent hero banners for responsive websites.
Batch-preparing social-media assets in the same ratio.
Adjusting photography prints to fit standard or custom frames.
Scaling UI mock-ups for different device viewports.
Bookmark the page and keep it handy whenever you need perfect proportions—anytime, anywhere.