How Many Pixels Do You Need to Print a Photo? 10×15, A4, A3 and Poster Sizes at 300 DPI

Short answer: for a sharp print, a photo needs about 300 pixels for every inch of the printed size. A 10×15 cm print needs 1181 × 1772 pixels, and an A4 page needs 2480 × 3508 pixels. Add your photo to the “Check my image for printing” tab of Imgovo’s DPI & Size Calculator and it shows which print sizes your file can handle. Everything runs in your browser, so nothing is uploaded.

How the numbers work

Pixels = inches × DPI, and 1 inch = 2.54 cm. A 10 cm side is 3.94 inches, and at 300 DPI that is 1181 pixels. For a deeper explanation of DPI and PPI, read What Is DPI? How to Convert cm and Inches to Pixels.

Rule of thumb:

• 300 DPI or more: sharp prints that you hold in your hand (photo prints, photo books, cards).
• 150–200 DPI: posters and large prints viewed from a distance.
• Below 150 DPI: pixels or softness may become visible.

Pixels needed for common print sizes

Print size	300 DPI	150 DPI
9 × 13 cm	1063 × 1535 px	531 × 768 px
10 × 15 cm	1181 × 1772 px	591 × 886 px
4 × 6 in	1200 × 1800 px	600 × 900 px
13 × 18 cm	1535 × 2126 px	768 × 1063 px
15 × 20 cm	1772 × 2362 px	886 × 1181 px
20 × 30 cm	2362 × 3543 px	1181 × 1772 px
5 × 7 in	1500 × 2100 px	750 × 1050 px
8 × 10 in	2400 × 3000 px	1200 × 1500 px
A5 (148 × 210 mm)	1748 × 2480 px	874 × 1240 px
A4 (210 × 297 mm)	2480 × 3508 px	1240 × 1754 px
A3 (297 × 420 mm)	3508 × 4961 px	1754 × 2480 px
50 × 70 cm poster	5906 × 8268 px	2953 × 4134 px
70 × 100 cm poster	8268 × 11811 px	4134 × 5906 px

The calculator lists these sizes as presets, so you can click one and read the pixel size directly. For the largest sizes, such as 70 × 100 cm at 300 DPI (about 98 megapixels), the calculation is correct but a phone or an older computer may not be able to process the file. The page warns you before it tries.

Does your photo have enough pixels?

Divide the photo’s pixels by the DPI you want. The result is the print size in inches.

Photo	Largest print at 300 DPI	Largest print at 150 DPI
3000 × 2000 px (6 MP)	25.4 × 16.9 cm	50.8 × 33.9 cm
4000 × 3000 px (12 MP phone)	33.9 × 25.4 cm	67.7 × 50.8 cm
6000 × 4000 px (24 MP camera)	50.8 × 33.9 cm	101.6 × 67.7 cm

You do not have to do the maths by hand. In the calculator, add the photo and read the results table: it lists the print sizes, the PPI your photo reaches at each size, how that compares with your target and a note.

Why a print is sometimes cropped

Photo paper does not always have the same proportions as your picture. When the ratios differ, a lab fills the paper and cuts off the edges.

Print size	Proportions
10 × 15 cm, 20 × 30 cm, 4 × 6 in	3:2
15 × 20 cm	4:3
8 × 10 in	5:4
5 × 7 in	about 1.4:1
9 × 13 cm	about 1.44:1
13 × 18 cm	about 1.38:1
A-sizes (A5, A4, A3)	about 1.41:1

A camera in 3:2 mode fits 10×15 and 20×30 prints exactly. A typical phone photo (4:3) fits 15×20 exactly, but needs a crop for 10×15. Cropping the photo yourself first lets you decide what stays in the picture, instead of leaving it to the lab.

Step by step: prepare a photo for printing

1. Check the size. Open the DPI & Size Calculator, add your photo and look at the DPI reached for the print size you want.
2. Crop to the print ratio. Open Crop Image and choose a ratio from “Photo & Print” (3:2, 4:5, 5×7, 8×10) or a paper preset (A4 2480 × 3508, A5, A6 or US Letter at 300 PPI). Drag the box so the important part stays inside.
3. Do not enlarge to fake detail. If the photo is too small, use the Image Resizer only to match the size, and know that enlarging adds pixels, not detail. How to resize an image without losing quality explains the limits.
4. Set the DPI label if your print service asks for it. In the “Change DPI label” tab of the calculator, “Download with DPI” writes the chosen DPI into the file. For JPG and PNG only the label in the file header changes; the pixels are not re-encoded.
5. Save at high quality. The calculator can re-save as JPG at 95% quality or as lossless PNG.
6. Order the print and, if the lab has an option such as “fit” or “no crop”, choose it after cropping to the right ratio.

Common mistakes

• Thinking 300 DPI in the file settings improves quality. The label changes the print size, not the sharpness. Only more pixels add real resolution.
• Printing a photo from social media or a messaging app. These copies are usually smaller and more compressed than the original. Use the original file.
• Cropping too tightly. If you crop away half of the picture, you also remove half of the pixels, and the DPI drops.
• Forgetting the margins. Some labs trim a few millimetres at the edge. Keep important details such as faces and text away from the border, and ask your lab if you need the exact trim.
• Expecting CMYK. Imgovo saves in the standard sRGB colour space, which most photo labs expect. It does not convert to CMYK.

Privacy

Checking, cropping and resizing run in your browser. Your photos are not uploaded, and the saved files contain pixel data only, so camera details and GPS location are not carried over.

Try it now

Open the DPI & Size Calculator, add your photo and see which print sizes it can handle. If you need a passport or ID photo, see Passport Photo Size in Pixels.