Formula and method
Pixel dimensions determine megapixels and potential print dimensions. Compressed file size cannot be predicted exactly from dimensions because format, content and quality settings also matter.
Assumptions and limits
- The browser can decode the selected image format.
- Image dimensions are processed locally.
- Print size does not account for cropping, bleed or printer margins.
Worked examples
6000 × 4000 camera image
The image contains 24 megapixels and has a 3:2 ratio. At 300 PPI it prints at 20 × 13.33 inches.
4032 × 3024 phone image
The image contains about 12.19 megapixels and has a 4:3 ratio. At 240 PPI it prints at 16.8 × 12.6 inches.
25 Megapixels Width and Height
Megapixels describe total pixel count, not shape. A 25 megapixel image has about 25 million pixels, but the width and height depend on aspect ratio.
Common examples are 5000 x 5000 for square, about 6124 x 4082 for 3:2, about 5774 x 4330 for 4:3, and about 6667 x 3750 for 16:9.
Megapixels and Print Size
After you know the pixel dimensions, print size depends on PPI. A 6124 x 4082 image prints at about 20.41 x 13.61 inches at 300 PPI.
For wall prints viewed farther away, 240 PPI or 150 PPI can produce larger output, but sharpness depends on the source image and viewing distance.
Common image dimensions and print uses
| Image size | Megapixels | 300 PPI print | Typical use |
|---|---|---|---|
| 4032 x 3024 | 12.19 MP | 13.44 x 10.08 in | Phone photo and standard prints |
| 6000 x 4000 | 24.00 MP | 20.00 x 13.33 in | Camera photo and wall prints |
| 1200 x 800 | 0.96 MP | 4.00 x 2.67 in | Web image or small card |
| 1600 x 900 | 1.44 MP | 5.33 x 3.00 in | HD thumbnail or presentation image |
Frequently asked questions
Is the uploaded image stored?
No. It remains on your device and is only decoded by your browser to read its dimensions.
Can dimensions predict JPEG file size?
Not accurately. Compression level, detail, noise, metadata and format have a major effect on file size.
What are megapixels useful for?
Megapixels give a quick total pixel count, but aspect ratio and final print PPI still determine the usable output size.
Can I use this for web images?
Yes. It helps check pixel dimensions, aspect ratio and whether a web image is large enough for its intended layout.
What width and height is 25 megapixels?
There is no single answer. 25 megapixels can be 5000 x 5000 at 1:1, about 6124 x 4082 at 3:2, about 5774 x 4330 at 4:3, or about 6667 x 3750 at 16:9.