Aspect Ratio Calculator – Free Dimension & Ratio Tool
About the Aspect Ratio Calculator
The Aspect Ratio Calculator works both directions: enter a width and height to find the simplified ratio, or enter a ratio and one dimension to calculate the matching width or height. It includes over 100 built-in presets across video, mobile, photography, social media, print, cinema, and mathematical ratios, each with a live visual preview.
It’s built for video editors, designers, and developers who need exact pixel dimensions for a specific ratio, like resizing a video for YouTube versus Instagram Stories. Once you have your dimensions, the Screen Resolution Simulator can show how they’ll look on different devices, and the CSS Border Radius Generator is useful if you’re styling the container that will hold your media.
The BigToolSite Team tested calculations across all preset categories, including uncommon ratios like the Golden Ratio and Cinemascope, to confirm the width, height, and simplified ratio always stay mathematically consistent.
How to Use the Aspect Ratio Calculator
- Enter a Width and Height in pixels to see the simplified ratio and live preview.
- Or enter a Ratio Width and Ratio Height to calculate the matching pixel dimensions.
- Browse 100+ presets by category — Video, Mobile, Photography, Social Media, Print, Cinema, or Mathematical.
- Click any preset to instantly apply its ratio and recalculate your dimensions.
- Enable Custom Ratio Mode to lock in a manual ratio while adjusting width or height.
Example Usage
Input: Width: 1920px, Ratio: 16:9
Output: Height: 1080px (simplified ratio 16:9)
Switch to an Instagram Story preset (9:16) with the same width, and the calculator instantly recalculates the height needed for a vertical layout.
Frequently Asked Questions
Enter the exact width and height in pixels, and the calculator will simplify it into a standard ratio format like 16:9 or 4:3.
Yes, enter your ratio and one known dimension (width or height), and the tool calculates the matching value automatically.
16:9 is the standard widescreen ratio used for most video and TV content, while 16:10 is slightly taller and common on laptop and monitor displays.
Yes, it includes presets for Instagram, TikTok, YouTube, Facebook, Twitter, LinkedIn, Pinterest, and more under the Social Media category.
Yes, it’s completely free with no signup required.
