Formula and method
megapixels = pixel width × pixel height ÷ 1,000,000
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.
Print size from a 6000 × 4000 image
| Density | Print size | Typical use |
|---|---|---|
| 300 PPI | 20 × 13.33 in | Close-viewed photo |
| 240 PPI | 25 × 16.67 in | Large quality print |
| 150 PPI | 40 × 26.67 in | Poster distance |
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.