How to Use This Tool
Enter Width and Height
Type the width and height of your image, video, or screen in any unit (pixels, inches, centimeters, etc.).
See the Aspect Ratio
The tool instantly calculates and displays the simplified aspect ratio, like 16:9 or 4:3.
Scale to a New Size
Enter a new width or height and the tool calculates the other dimension to keep the same ratio.
Use a Preset
Click any of the common ratio presets to fill in a standard ratio instantly.
Frequently Asked Questions
Is this tool really free?
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Yes, completely free with no limits and no sign-up. Everything runs in your browser.
Is my data sent to a server?
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No. All calculations happen directly in your browser. Nothing you type is ever sent anywhere.
What is an aspect ratio?
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An aspect ratio is the proportional relationship between width and height, expressed as two numbers like 16:9. It describes the shape of an image, video, or screen.
What are common aspect ratios?
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16:9 (widescreen video and monitors), 4:3 (old TV and presentations), 1:1 (square, Instagram), 9:16 (vertical video), 21:9 (ultrawide), and 3:2 (DSLR photos).
How does the scaling work?
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Enter a new width and the tool calculates the height that keeps the same aspect ratio, or enter a new height and the tool calculates the width.
What are the preset buttons?
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Quick-select buttons for common ratios like 16:9, 4:3, 1:1, and more. Click one to fill in that ratio instantly.
Can I use any unit?
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Yes. The aspect ratio is a proportion, so it works regardless of whether your dimensions are in pixels, inches, centimeters, or any other unit.
How is the ratio simplified?
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The tool finds the greatest common divisor of your width and height and divides both by it to get the simplest ratio.
Does it update instantly?
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Yes. All results recalculate as soon as you change any input.
Can I copy the ratio?
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Yes. Click the copy button next to the calculated ratio to put it on your clipboard.
What Is Aspect Ratio Calculator?
Aspect Ratio Calculator is a free tool that finds the aspect ratio of any width and height, scales dimensions proportionally, and offers common ratio presets - all right in your browser. Enter your dimensions and see the simplified ratio instantly. Nothing you type is ever sent anywhere - all math runs locally on your device.
Use the scaling feature to resize an image, video, or screen while keeping the same proportions. Common presets like 16:9, 4:3, and 1:1 are available in one click.
Features Explained
Simplified Aspect Ratio
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Enter any width and height and see the ratio reduced to its simplest form, like 16:9, 4:3, or 3:2.
Proportional Scaling
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Enter a new width or height and the tool calculates the other dimension to keep the same aspect ratio. Perfect for resizing without distortion.
Common Presets
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Quick-select buttons for popular ratios: 16:9, 4:3, 1:1, 9:16, 21:9, 3:2, 2:3, and more. Click one to fill in that ratio instantly.
Works with Any Unit
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Pixels, inches, centimeters, or any other unit. The ratio is a proportion, so the unit does not matter.
Copy the Ratio
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Click the copy button to put the calculated ratio on your clipboard in one click.
Instant Results
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All calculations update live as you type. No button needed.
Scale in Either Direction
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Enter a new width to find the matching height, or enter a new height to find the matching width.
GCD Simplification
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The tool automatically finds the greatest common divisor to give you the simplest possible ratio.
Clean Layout
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Inputs, ratio, and scaling are all displayed clearly so you can read every value at a glance.
100% Browser-Based
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All math runs directly in your browser. Nothing you type is ever sent to any server.
Who Is This Tool For?
Video Editors
Calculate and maintain the correct aspect ratio when resizing video projects for different platforms.
Photographers
Find the aspect ratio of your photos and scale them for prints, web, and social media.
Graphic Designers
Scale design assets proportionally and verify aspect ratios for banners, ads, and layouts.
Web Developers
Calculate responsive image and video dimensions that maintain the correct aspect ratio.
UI/UX Designers
Design interfaces with correct proportions for different screen sizes and orientations.
Social Media Managers
Find the right dimensions for Instagram (1:1), Stories (9:16), YouTube (16:9), and other platforms.
YouTubers
Verify that thumbnails and video exports match the standard 16:9 aspect ratio.
Filmmakers
Calculate frame dimensions for cinema ratios like 2.39:1, 1.85:1, and 16:9.
Students
Learn about aspect ratios and proportional scaling for math and media classes.
Teachers
Demonstrate aspect ratios and proportional relationships during math and design lessons.
Print Designers
Scale print layouts proportionally and verify that artwork fits the target ratio.
Architects
Calculate proportional dimensions for floor plans, elevations, and presentation layouts.
Game Developers
Set correct aspect ratios for game windows, UI elements, and texture atlases.
Monitor Shoppers
Compare the shape of different monitors by checking whether they are 16:9, 16:10, or 21:9.
Presentation Designers
Verify slide dimensions match the projector or screen ratio (usually 16:9 or 4:3).
E-commerce Sellers
Size product photos to a consistent ratio for clean, uniform listing pages.
Email Designers
Scale header images proportionally to fit email template widths.
Streamers
Set up overlay elements and webcam frames at the correct aspect ratio.
Advertisers
Scale ad creatives proportionally for different banner sizes and placements.
Real Estate Photographers
Maintain consistent photo ratios across listing images.
Drone Operators
Verify that aerial footage and stills are at the expected aspect ratio.
3D Modelers
Set render dimensions to the correct ratio for final output.
Bloggers
Scale featured images and inline photos to a consistent ratio across posts.
Anyone
Quickly find the aspect ratio of any dimensions or scale them proportionally.
Tips for Best Results
Common video ratios
16:9 is standard widescreen (YouTube, TV). 4:3 is old TV. 9:16 is vertical (Stories, TikTok, Reels). 21:9 is ultrawide cinema.
Common photo ratios
3:2 is standard DSLR. 4:3 is micro four thirds and older cameras. 1:1 is square.
Use presets for quick setup
Click a preset button to fill in a standard ratio instantly instead of typing dimensions.
Scale without distortion
Enter a new width and the tool finds the matching height (or vice versa) so your content keeps its original proportions.
Any unit works
Pixels, inches, centimeters, feet - the ratio is the same regardless of the unit you use.
Copy the ratio
Click the copy button to grab the simplified ratio for your notes, specs, or documentation.
Results update instantly
Change any input and the ratio and scaled dimensions recalculate immediately.
Check before resizing
Before resizing an image or video, enter its current dimensions here to see the ratio, then use the scaler to find the new size.
1920x1080 is 16:9
The most common video resolution. Other 16:9 resolutions: 1280x720 (HD), 2560x1440 (QHD), 3840x2160 (4K).
Privacy is built in
Nothing you type is ever sent to any server. All math runs in your browser.
Privacy & Security
This tool runs 100% in your browser. Your files stay entirely on your own device. Nothing is uploaded, nothing is shared, and no server, advertiser, or third party has access to your files.
If a tool saves your work on your own device, you can remove it at any time using the Clear All button. Some tools rely on an external service to return their result; in those cases, only the minimum data required for the request is sent, and never your files or content. Any ads shown on this page run in an isolated frame and cannot read, touch, or transmit anything you upload, paste, type, or download here. Advertisers may see standard visit information like your IP address and which page you're on, as described in our Privacy Policy, but your data itself stays fully under your control.
