Aspect Ratio Calculator
Stop guessing dimensions. Calculate the perfect width and height for any video or image. Ensure your content fits on Instagram, YouTube, and monitors without getting stretched.
Calculator
Aspect Ratio
16:9
Dimensions: 1920 × 1080 px
Result
Enter values to see the calculation result
Common Presets
Video & TV
Cinema
Photography
Social Media
Displays
Why Does Ratio Matter?
Aspect ratio is just a fancy way of saying "the shape of the rectangle." It tells you how wide an image is compared to how tall it is. It's written as Width:Height (e.g., 16:9).
For example, a standard TV is 16:9. That means for every 16 units of width, it has 9 units of height. If you try to display a 4:3 image (like an old TV show) on it, you get black bars on the sides because the shapes don't match. Using the correct ratio ensures your content uses the full screen without being cropped or stretched.
Why Resolution is Different
Resolution refers to the actual number of pixels (e.g., 1920x1080), while aspect ratio describes the shape. You can have a tiny 16:9 image and a huge 16:9 image — they are the same shape, just different quality. Our calculator helps you find the right resolution to match your desired shape.
Common Mistakes to Avoid:
- ×Stretching a 4:3 image to fit a 16:9 screen (makes people look short and wide)
- ×Uploading a horizontal video to TikTok (it will be tiny with huge black spaces)
- ✓The Fix: Use this calculator to find the exact pixel dimensions you need to crop or resize to.
Cheat Sheet: Common Ratios
16:9
📺Widescreen (YouTube/TV)
The standard for almost all modern video. Used by YouTube, Netflix, and TV broadcasts.
Popular Sizes:
1920×1080, 3840×2160 (4K)
9:16
📱Vertical (TikTok/Reels)
The mobile standard. If you are making a Story, Reel, or TikTok, use this.
Popular Sizes:
1080×1920, 720×1280
1:1
⬛Square (Instagram)
A perfect square. Used to be the only option on Instagram. Good for profile pics.
Popular Sizes:
1080×1080, 500×500
4:3
🖥️Classic / iPad
The old "box" TV shape. Also roughly the shape of an iPad screen.
Popular Sizes:
1024×768, 1600×1200
21:9
🎬Ultrawide
Super wide format used in movies and curved gaming monitors.
Popular Sizes:
2560×1080, 3440×1440
4:5
📷Portrait (Insta Feed)
Slightly taller than a square. Best for Instagram posts as it fills more screen.
Popular Sizes:
1080×1350
How to Use
Pick a Preset
Choose 16:9, 4:3, etc. from the dropdown if you know it.
Enter One Number
Type the width OR height you have (e.g. 1920).
Get the Other
We instantly calculate the matching dimension.
Or Use Custom
Enter both dimensions to find out what ratio they are.
💡 Quick Tips for Creators
- →YouTube: Always use 16:9 (1920x1080). If you upload other ratios, YouTube adds black bars.
- →Instagram Stories/TikTok: Use 9:16 (1080x1920). It's just 16:9 turned sideways.
- →Instagram Posts: 4:5 (1080x1350) takes up the most screen space on a phone feed.
- →Resizing: Lock the aspect ratio in Photoshop/Canva so your image doesn't get squished.
Frequently Asked Questions
What size should my YouTube video be?▼
YouTube videos should be 16:9. The best quality is 1920×1080 (1080p). You can also do 1280×720 (720p) or 3840×2160 (4K). They all share the same 16:9 shape.
How do I fix a stretched image?▼
An image looks stretched because you changed its width or height without changing the other one proportionally. Use this calculator: enter the original width/height, then enter the NEW width you want. It will tell you the correct new height to keep it looking normal.
What aspect ratio is best for Instagram?▼
For Posts, use 4:5 (1080×1350) because it takes up the most vertical space on a user's phone. For Stories and Reels, you MUST use 9:16 (1080×1920) or it will be cropped.
Is 1920x1080 the same as 16:9?▼
Yes! 1920×1080 is the resolution (number of pixels), and 16:9 is the aspect ratio (the shape). If you divide 1920 by 120 you get 16. If you divide 1080 by 120 you get 9.
What is the ratio for iPhone wallpapers?▼
Most modern smartphones (iPhones, Samsungs) are roughly 9:19.5 or 9:20. Using a 9:16 (1080×1920) image usually works fine, but might be zoomed in slightly.