About the Print Size Calculator
This print size calculator answers two questions: how large can I print this image, and how many pixels do I need for a given print? Enter the image’s width and height in pixels and the print resolution in pixels per inch (PPI, often called DPI) to get the print size in inches and centimetres, or switch modes and enter a print size to get the pixel dimensions required.
Photographers, designers and anyone ordering canvases, posters or photo-book pages can use it to avoid blurry, pixelated prints. The table rates the image against standard print sizes from 4 × 6 to 24 × 36 inches, showing the effective PPI each size would get and whether the result will look excellent, good, fair or low quality.
300 PPI is the common standard for prints viewed at arm’s length; 200–240 PPI is usually fine for larger prints, and big posters or banners viewed from across a room can go to 100–150 PPI. The ratings assume the image is fitted inside the print with its long side matched to the print’s long side.
How to use the print size calculator
- 1Choose whether you want the print size from your pixels, or the pixels needed for a print.
- 2Enter the image width and height in pixels, or the print size in inches or centimetres.
- 3Set the print resolution — 300 PPI for photo prints, lower for large posters.
- 4Read the result and check the table for standard print sizes.
- 5Pick the largest size rated Good or Excellent for sharp results.
Formula and method
Print size is the pixel count divided by the print resolution. A 6000-pixel-wide image at 300 pixels per inch is 20 inches wide; at 150 PPI it would be 40 inches wide but each pixel would be twice as large. Working backwards, multiply the print dimension in inches by the PPI to get the pixels you need, rounding up to a whole pixel; centimetres are converted at exactly 2.54 cm per inch.
For the table, the image is fitted inside each standard print size with its long side along the print’s long side, and the effective resolution is the lower of the two directions’ pixels-per-inch — the side that limits sharpness. Cropping to fill a different aspect ratio uses fewer pixels and slightly lowers the effective PPI.
- PPI
- Pixels per inch on the print (often called DPI)
- pixels
- Image width or height in pixels
Worked examples
24 MP photo (6000 × 4000) at 300 PPI
6000 ÷ 300 = 20 inches and 4000 ÷ 300 = 13.33 inches, or about 50.8 × 33.9 cm. A 12 × 18 inch print would get 333 PPI — excellent quality.
Pixels for an 8 × 10 inch print
At 300 PPI an 8 × 10 inch print needs 8 × 300 = 2400 by 10 × 300 = 3000 pixels, a total of 7.2 megapixels.
A3 poster (29.7 × 42 cm) at 200 PPI
29.7 cm is 11.69 inches and 42 cm is 16.54 inches. Multiplying by 200 PPI and rounding up gives 2339 × 3308 pixels, about 7.7 MP.
12 MP phone photo (4032 × 3024) at 240 PPI
At 240 PPI, 4032 × 3024 pixels prints at 16.8 × 12.6 inches, so a phone photo comfortably covers an 11 × 14 inch print.
Frequently asked questions
Is DPI the same as PPI?+
Strictly, PPI is pixels per inch in the image and DPI is ink dots per inch from the printer, but print labs and software use “DPI” to mean PPI. When a lab asks for 300 DPI, they mean 300 image pixels per printed inch.
What resolution do I need for a good print?+
300 PPI is the standard for photos viewed up close. 200–240 PPI looks nearly identical for most prints, and large posters viewed from a few metres away can use 100–150 PPI without visible pixelation.
Does changing DPI in Photoshop make my print bigger?+
Changing the DPI field without resampling only changes the recorded print size, not the pixels. To print larger at the same sharpness you need more pixels — upscaling can help a little but cannot invent real detail.
How many pixels do I need for a 4 × 6 print?+
At 300 PPI, a 4 × 6 inch print needs 1200 × 1800 pixels (2.16 MP). Almost any modern phone or camera image is more than enough.
Why does my print look cropped?+
Camera files are usually 3:2 or 4:3, while 8 × 10 and 11 × 14 prints are 4:5 and 11:14. The lab trims the image to fill the paper, so leave space around your subject or choose a print size that matches your aspect ratio.