Image DPI
Calculator
Find the DPI of an image, the pixels you need for a print, or the largest size you can print sharply. Free and instant.
- 100% Free
- No Installation
- Works on All Devices
- Fast & Secure
Calculate Your DPI
Choose a mode, enter your pixel size or print size and see the result straight away.
Everything is calculated in your browser. If you load an image, only its pixel size is read and the file is not uploaded.
What Is an Image DPI Calculator?
DPI stands for dots per inch. It tells you how many dots of ink, or pixels, are packed into one inch of a printed picture. The more dots per inch, the sharper the print. An image DPI calculator does the maths for you: it connects the size of your image in pixels to the size of the print in inches, centimetres or millimetres, so you can see whether a photo is good enough for a given print before you pay for it.
DPI vs PPI: Is There a Difference?
Strictly speaking, PPI (pixels per inch) describes how many pixels an image has per inch on a screen or in a file, and DPI describes how many ink dots a printer places per inch. In everyday use, people mix the two terms, and most online forms and print shops simply say DPI when they mean the pixel density of the picture. This calculator uses DPI in that everyday sense.
How to Calculate DPI
The formula is simple: DPI equals the number of pixels divided by the print size in inches. For example, an image that is 3000 pixels wide printed 10 inches wide has a resolution of 300 DPI. If the same image is printed 20 inches wide, it drops to 150 DPI and looks softer.
How to Use This Calculator
1. Find the DPI of an image
Enter the width and height of your image in pixels, then the print size you want. You can also press Use the size of my image to read the pixel size straight from a file. The tool shows the DPI, a quality rating and the exact print size.
2. Find how many pixels you need
Enter the print size and the DPI you want, such as 300. The calculator shows the pixel width and height your image must have, plus the megapixels. This is helpful before you take a photo or order a design.
3. Find the largest print size
Enter the pixel size of your image and a DPI. The calculator tells you the biggest print you can make without losing sharpness.
Recommended DPI for Different Uses
| Use | Recommended DPI |
|---|---|
| Photo prints and magazines | 300 DPI |
| Brochures and flyers | 250 to 300 DPI |
| Office documents | 150 to 200 DPI |
| Posters viewed from a distance | 100 to 150 DPI |
| Large banners and billboards | 30 to 100 DPI |
| Websites and screens | 72 to 96 PPI, but pixel size matters most |
Pixels Needed at 300 DPI for Common Print Sizes
| Print size | Pixels at 300 DPI |
|---|---|
| 4 x 6 inches | 1200 x 1800 |
| 5 x 7 inches | 1500 x 2100 |
| 8 x 10 inches | 2400 x 3000 |
| A4 (210 x 297 mm) | 2480 x 3508 |
| A3 (297 x 420 mm) | 3508 x 4961 |
| A2 (420 x 594 mm) | 4961 x 7016 |
| 35 x 45 mm passport photo | 413 x 531 |
For passport and visa sizes by country, use our Passport / Visa Photo Resizer.
Can You Increase the DPI of an Image?
Changing the DPI number stored in a file does not add detail. A photo with 1200 x 1800 pixels is still 1200 x 1800 pixels, whether it is labelled 72 DPI or 300 DPI. What changes is the size it prints at by default. To print larger without losing sharpness, you need more real pixels, which means taking the photo again at a higher resolution. Enlarging a small picture with software can make it bigger, but it cannot create detail that was never captured.
Does DPI Matter for Websites and Screens?
No. On a screen only the width and height in pixels matter. The DPI value inside a web image has no effect on how it looks in a browser. If your goal is a lighter web image, reduce the pixel size or the file size instead, for example with the Compress Image to Exact KB tool.
Check What Is Stored in Your File
Photos can also hold hidden camera and location details. Use the EXIF Metadata Remover and Viewer to see them, and the All-in-One Image Converter to change the file type before printing.
Frequently Asked Questions
What is DPI in an image?
DPI means dots per inch. It describes how many dots or pixels fit in one inch of a print. Higher DPI gives a sharper printed picture.
How do I calculate the DPI of an image?
Divide the width of the image in pixels by the print width in inches. For example, 3000 pixels printed at 10 inches wide gives 300 DPI. The calculator does this for width and height automatically.
What is the best DPI for printing photos?
300 DPI is the standard for sharp photo prints. For large posters that people view from a distance, 100 to 150 DPI is usually enough.
How many pixels do I need for an 8 x 10 inch print?
At 300 DPI you need 2400 x 3000 pixels, which is about 7.2 megapixels.
What DPI should I use for a website image?
DPI does not affect how an image looks on a screen. Only the pixel width and height matter, so focus on the pixel size and the file size.
Does changing the DPI change the image quality?
Changing only the DPI value does not add or remove pixels, so the picture itself stays the same. It only changes the default print size. Real quality depends on the number of pixels.
Why does my photo show 72 DPI?
Many cameras, phones and apps store 72 or 96 as a default label. It does not describe the real sharpness. What matters is the pixel size divided by the print size, which this calculator works out.
Is my image uploaded when I use the calculator?
No. Everything is calculated in your browser. If you load an image to fill in its size, only the pixel size is read and the file stays on your device.