Free Online Aspect Ratio Calculator — Calculate Aspect Ratios Instantly
Calculate aspect ratios instantly with our free online aspect ratio calculator. Enter any width and height to find the simplified aspect ratio, or use the presets to calculate missing dimensions for common formats like 16:9, 4:3, and 21:9. Perfect for video editors, web designers, photographers, and anyone working with responsive layouts or screen resolutions. Also calculate exact pixel dimensions from a target aspect ratio.
Enter the width and height to calculate the simplified aspect ratio.
The simplified aspect ratio is calculated automatically.
Use the target ratio tool to find missing dimensions when resizing.
Tips for Using the Aspect Ratio Calculator
- The simplified ratio is calculated using the greatest common divisor (GCD) of width and height.
- Use the target ratio calculator to find the matching dimension when resizing images while preserving aspect ratio.
- Common presets: 16:9 (widescreen), 4:3 (standard), 21:9 (ultrawide), 1:1 (square), 3:2 (photo), 9:16 (vertical video).
Frequently Asked Questions — Aspect Ratio Calculator
Is the aspect ratio calculator free?
Yes, completely free. No registration, no hidden charges. All calculations happen locally in your browser.
How is the aspect ratio calculated?
The tool calculates the greatest common divisor (GCD) of the width and height values, then divides both by the GCD. For example, 1920×1080 has a GCD of 120, giving 1920/120 : 1080/120 = 16:9.
What is the most common aspect ratio?
16:9 is the most common aspect ratio for modern displays, videos, and streaming content. 4:3 was standard for older TVs and monitors.
Can I calculate missing dimensions?
Yes, enter a target aspect ratio and one dimension (width or height), and the tool calculates the matching dimension.
What are aspect ratios used for?
Aspect ratios are used in video production, web design, photography, responsive layouts, screen resolutions, printing, and any context where proportional scaling matters.
What does the decimal value mean?
The decimal value is width divided by height. For example, 16:9 = 1.778, 4:3 = 1.333, and 1:1 = 1.0.
Can I use values other than pixels?
Yes, the calculator works with any units (pixels, inches, cm, etc.) as long as both width and height use the same unit.