How to use the Image Pixel Checker
- Click the upload box (or drag an image onto it) and choose a JPG, PNG, GIF, WEBP or BMP file.
- Read the width, height, megapixels, file size, format, aspect ratio and orientation.
- Change the DPI box to see how large the image can be printed at that quality, and read the recommendations below the result.
Formulas used
Megapixels = Total pixels ÷ 1,000,000
Print size (inches) = Pixels ÷ DPI
Pixels needed for a print = Inches × DPI
Worked examples
4000 × 3000 px = 12,000,000 pixels = 12 MP.
3000 × 2000 px at 300 DPI prints at 3000 ÷ 300 = 10 inches by 2000 ÷ 300 = 6.67 inches.
An 8 × 10 inch print at 300 DPI needs 2400 × 3000 pixels.
Pixels needed for common print sizes
At 300 DPI, which is the usual standard for sharp prints, you need roughly these pixel dimensions:
| Print size | Pixels at 300 DPI |
|---|---|
| 4 x 6 inch photo | 1200 x 1800 px |
| 5 x 7 inch photo | 1500 x 2100 px |
| 8 x 10 inch print | 2400 x 3000 px |
| A4 page (8.27 x 11.69 inch) | 2481 x 3507 px |
Common mistakes to avoid
- Enlarging a small image. Making a picture bigger in an editor does not add real detail. It only stretches the pixels it already has.
- Confusing DPI with pixel size. The pixel dimensions decide quality. A DPI number stored in the file only suggests a print size.
- Using huge files on web pages. A 12 MP photo straight from a phone is far larger than a web page needs and slows loading.
- Checking a screenshot instead of the original. A screenshot has the pixel size of your screen, not of the original photo.
Frequently asked questions
Is my image uploaded?
No. The image is read in your browser, so its details are never sent to a server.
What is a good DPI for printing?
300 DPI is the usual target for sharp photo prints. Large posters viewed from a distance are often printed at 150 DPI or lower.
What image size should I use on a website?
Most web pages look sharp with images 1200 to 2000 pixels wide. Keep the file as small as you can without visible loss, ideally a few hundred KB or less.
What is aspect ratio?
It is the ratio of width to height, such as 16:9 or 4:3. Keeping the same ratio when you resize stops the image looking stretched.
Does a bigger file size mean a better image?
Not always. File size depends on the format and compression as well as the pixels. Two images with the same dimensions can have very different file sizes.
Why does the tool not resize or compress my image?
This tool only checks and reports. Use an image editor or a compression tool to resize, and then check the new image here.
Does the DPI stored in an image file matter?
Only as a suggestion for print size. What decides sharpness is the number of pixels. Use the DPI box on this page to see how large the image can print at the quality you want.
How do I make a photo suitable for a website?
Resize it to the width it will be displayed at (often 1200 to 2000 pixels for a full-width image), then compress it or save it as WEBP. Check the new size here afterwards.