Aspect Ratio Finder – Find Perfect Image & Video Dimensions
Enter a width and a height, or upload an image, and the Aspect Ratio Finder shows the simplified ratio, decimal value, orientation, and the closest standard ratio. It also calculates a missing dimension for a target ratio such as 16:9.
Overview
Uploading a photo only to see it crop awkwardly or stretch out of shape is frustrating. Guessing dimensions rarely works, and doing the math by hand takes time. The Aspect Ratio Finder gives you the exact ratio, orientation, and matching dimensions in seconds.
Aspect ratio is the proportion between the width and the height of an image, video, screen, or frame. It is written as two numbers separated by a colon, such as 16:9 or 4:3. A 1920 × 1080 frame and a 1280 × 720 frame both simplify to 16:9. Their pixel counts differ, but the shape is the same.
Aspect ratio, dimensions, and resolution are different things
- Dimensions are the pixel counts of a file, such as 4032 × 3024.
- Aspect ratio is the proportion of those two numbers. For 4032 × 3024 it is 4:3.
- Resolution relates pixels to physical size, such as pixels per inch when printing. It says nothing about the shape of the frame.
A small 640 × 480 thumbnail and a large 4032 × 3024 photo share the same 4:3 ratio, even though one has far more pixels.
Features
Instant calculation
Enter a width and height to get the simplified ratio, decimal value, orientation, and closest common ratio.
Preset ratios
Choose 1:1, 4:3, 3:2, 16:9, 9:16, 4:5, 5:4, or 21:9. The proportions stay locked, so changing one dimension updates the other.
Image upload
Upload a JPG, PNG, GIF, or WebP file and the Aspect Ratio Finder reads its real pixel width and height.
Bulk checking
Select several images at once and compare their dimensions, ratios, and orientations in one table.
Visual preview
See a proportional preview of the result next to the numbers.
Privacy first
Images are read inside your browser and are not sent to a server.
Video files cannot be uploaded. For a video, type its width and height into the two boxes.
How to Use the Aspect Ratio Finder
Find the ratio from dimensions
Enter the width and height in pixels. The Aspect Ratio Finder reduces them to the simplest ratio and shows the decimal value, orientation, and closest standard ratio.
Find a missing dimension
Choose a preset such as 16:9 and enter the one dimension you already know. The other dimension is filled in automatically.
Check an image
Select or drag in a JPG, PNG, GIF, or WebP file. Its natural pixel size is read in your browser and the ratio is shown.
Check many images
Select several files together. The results table lists each file's dimensions, simplified ratio, closest common ratio, and orientation, making inconsistent proportions easy to spot.
How to Find an Aspect Ratio by Hand
To simplify a ratio, divide both numbers by their greatest common divisor (GCD).
For 1920 × 1080, the GCD is 120. Then 1920 ÷ 120 = 16 and 1080 ÷ 120 = 9, so the ratio is 16:9.
Find a missing dimension
New height = new width × (original height ÷ original width)
For example, an image is 1920 × 1080 and you need it 1600 pixels wide. The new height is 1600 × (1080 ÷ 1920) = 900, so the result is 1600 × 900.
The decimal value is simply width ÷ height. For 4:3 it is 1.333, and for 16:9 it is 1.778.
Common Aspect Ratio Examples
| Resolution | Aspect ratio | Orientation | Common use |
|---|---|---|---|
| 1280 × 720 | 16:9 | Landscape | HD video |
| 1920 × 1080 | 16:9 | Landscape | Full HD video |
| 2560 × 1440 | 16:9 | Landscape | QHD displays |
| 3840 × 2160 | 16:9 | Landscape | 4K UHD video |
| 1080 × 1920 | 9:16 | Portrait | Vertical video |
| 1080 × 1080 | 1:1 | Square | Square social posts |
| 1080 × 1350 | 4:5 | Portrait | Portrait social posts |
| 4032 × 3024 | 4:3 | Landscape | Many phone photos |
| 3000 × 2000 | 3:2 | Landscape | Many camera photos |
| 1920 × 1200 | 8:5 (16:10) | Landscape | Some laptop screens |
| 2560 × 1080 | 64:27 (about 21:9) | Landscape | Ultrawide displays |
| 2048 × 1080 | 256:135 | Landscape | 2K cinema |
| 1366 × 768 | 683:384 (about 16:9) | Landscape | Older laptop screens |
Not every size reduces to a familiar ratio. For example, 1366 × 768 is 683:384, very close to 16:9 but not exactly 16:9. The Aspect Ratio Finder shows both the exact ratio and the closest standard ratio.
Aspect Ratios for Popular Platforms
Platforms change their recommendations from time to time, so check the platform's own help page before a final export.
| Use | Commonly used ratio | Example size |
|---|---|---|
| Standard YouTube video | 16:9 | 1920 × 1080 |
| YouTube Shorts, Reels, Stories, TikTok | 9:16 | 1080 × 1920 |
| Square social post | 1:1 | 1080 × 1080 |
| Portrait social post | 4:5 | 1080 × 1350 |
| Link preview image | About 1.91:1 | 1200 × 630 |
| Pinterest pin | 2:3 | 1000 × 1500 |
| Common print sizes | 2:3 (4 × 6 in), 4:5 (8 × 10 in) | – |
Changing an Image From One Ratio to Another
You cannot change an image's ratio without giving something up. There are three options.
Crop
Cut away part of the picture. Turning a 1440 × 1080 image (4:3) into 16:9 at the same width gives 1440 × 810, so 270 pixels of height (25%) are removed.
Add padding
Keep the whole picture and fill the empty space. A 1440 × 1080 image placed in a 1920 × 1080 frame gets 240 pixels of empty space on each side.
Stretch
Force the image to the new size. This distorts the picture, so it is rarely a good choice.
Common Aspect Ratio Problems
Distorted images
Resizing without keeping the original proportions stretches or squashes the picture. Check the original ratio first and scale both sides by the same amount.
Wrong platform dimensions
If your image has a different ratio from the platform's frame, it may be cropped, padded, or moved when displayed.
Exact ratio versus nearest ratio
The exact ratio describes your actual image. The nearest standard ratio tells you which common format it most resembles.
Slow manual checks
Checking many files one by one takes time. Bulk checking shows all of them in one table.
Frequently Asked Questions
What is the aspect ratio?
It is the proportion between the width and the height of an image or video, written as two numbers such as 16:9. It describes the shape of the frame, not its pixel size.
How do I find the aspect ratio of an image?
Upload the image, or type its width and height into the Aspect Ratio Finder. The exact ratio and the closest standard ratio are shown right away.
How do I calculate an aspect ratio by hand?
Divide the width and the height by their greatest common divisor. For 1920 × 1080, the GCD is 120, which gives 16:9.
What is the difference between aspect ratio and resolution?
Aspect ratio is the shape of the frame. Resolution is the amount of detail, measured in pixels or in pixels per inch for print. Two images can have very different resolutions and the same aspect ratio.
Are 1280 × 720, 1920 × 1080, and 2560 × 1440 all 16:9?
Yes. All three simplify exactly to 16:9.
Is 1366 × 768 exactly 16:9?
No. It reduces to 683:384, which is very close to 16:9 but not identical.
What is the aspect ratio of a phone photo?
Many phone cameras save photos at 4:3, such as 4032 × 3024. It depends on the camera and the mode, so check the actual file.
How do I find a missing width or height?
Select a preset ratio and enter the dimension you know. The Aspect Ratio Finder fills in the other one.
Does resizing change the aspect ratio?
Not if both sides are scaled by the same amount. Scaling 4000 × 3000 down to 800 × 600 keeps the ratio at 4:3. The ratio changes only when the sides are scaled differently or the image is cropped.
How do I convert 4:3 to 16:9 without cropping?
You cannot do it without a trade-off. You can crop, add padding, or stretch the image. Adding padding keeps the whole picture without distortion.
Which aspect ratio is best for YouTube, Instagram, or TikTok?
16:9 is common for standard YouTube videos. 9:16 is common for TikTok, Instagram Reels, Stories, and YouTube Shorts. Instagram feed posts commonly use 1:1 and 4:5.
Can I check several images at once?
Yes. Select multiple files and the Aspect Ratio Finder lists each file's dimensions, ratio, closest standard ratio, and orientation in one table.
Are my images uploaded to a server?
No. Images are read inside your browser, and the calculation happens on your device.
Does the Aspect Ratio Finder work on mobile?
Yes. It works in modern mobile browsers and the layout adjusts to smaller screens.