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Init Ratio & Size is an online tool that helps you calculate dimensions by aspect ratio quickly and accurately прямо in your browser, with no installation required and no data upload. Simply choose a ratio (16:9, 4:3, 1:1, A4, A3, etc.), lock either the width or height, enter the value – and the tool will instantly calculate the remaining dimension.
Introduction
Init Ratio & Size is designed for designers, developers, marketers and content creators who need fast and precise size conversion. All calculations are processed 100% on the client side using JavaScript, ensuring high performance, full privacy and zero data storage. The tool supports common aspect ratios, standard paper sizes (A5, A4, A3, Letter…), as well as fully custom ratios.
With just a few simple actions, you can obtain accurate dimensions for images, videos, banners, slides, print layouts and web design.
Real-world Use Cases
- Graphic design: Quickly calculate image sizes based on standard ratios
- Video & social media: Convert between 16:9, 9:16, 1:1 for platforms
- Printing: Work precisely with A4, A3, A5 and Letter formats
- Web design: Maintain correct banner and thumbnail proportions
- Education: Demonstrate aspect ratio and size relationships
- Marketing: Standardize sizes for posters, social posts and ads
Main Features
- Lock one dimension: Lock width or height as the reference
- Automatic ratio calculation: Instantly computes the other side
- Common aspect ratios: 16:9, 4:3, 1:1, 9:16, 21:9…
- Standard paper sizes: A5, A4, A3, Letter, Legal…
- Custom ratio input: Freely define your own width–height ratio
- Swap width / height: Instantly invert dimensions
- Multiple units supported: px, mm, cm, inch
- 100% client-side processing: No upload, no data storage
How to Use
- Select an aspect ratio or a paper size
- (Optional) Enter a custom ratio if you do not use presets
- Choose whether to lock the width or lock the height
- Enter the value of the locked dimension
- Select the measurement unit (px, mm, cm, in)
- Click “Calculate size” to get the result
- Use the calculated size for design, print or development
Why Choose Init Ratio & Size?
- Completely free, no usage limits
- No account required, no data tracking
- Instant calculation with high accuracy
- Suitable for both digital design and printing workflows
- Button-first, clean and intuitive user interface
- Fully responsive on PC, tablet and mobile devices
Whether you are designing banners, resizing images, producing videos or preparing print layouts – Init Ratio & Size helps you convert dimensions by ratio quickly, accurately and safely right inside your browser.
