Print Size Calculator - How Big Can I Print My Photo?

About the Print Size Calculator

Before sending a photo to a print shop, or choosing a frame, it helps to know how large the picture can be printed while still looking sharp. That depends on two things: how many pixels the image has, and how many of them you want in each inch of paper. With those two numbers, the largest print is a simple division, but it is easy to lose track of which size suits which photo.

This print size calculator works out the print size of an image from its pixel dimensions and a chosen print resolution in DPI. It gives the size in inches and centimetres, the image's megapixels, the resolution you would get at a list of standard print sizes, and how large you could go for a poster at 150 DPI.

How to Use the Print Size Calculator

Enter the image width and image height in pixels.

Enter the print resolution you want, in DPI. 300 DPI is the usual standard for photo-quality prints; 200 is good for most framed prints, and 150 is usually fine for posters.

The calculator divides the pixels by the DPI and checks the image against common print sizes.

How Print Size Is Worked Out

  print width   =  pixel width ÷ DPI       (inches)
  print height  =  pixel height ÷ DPI
  centimetres   =  inches × 2.54
  DPI at a set size  =  the smaller of (pixels ÷ inches) for each side

Step-by-Step Example

A 24 megapixel photo, 6000 × 4000 pixels, at 300 DPI.

  Width:    6000 ÷ 300 = 20 in
  Height:   4000 ÷ 300 = 13.3 in
  Metric:   20 × 2.54 = 50.8 cm;  13.33 × 2.54 = 33.9 cm

So the photo prints at 20 × 13.3 inches, about 50.8 × 33.9 cm, at photo quality. For a poster seen from a few steps away, 150 DPI doubles that to 40 × 26.7 inches.

The standard sizes line shows how much resolution each common print would have:

  4 × 6 in    1000 DPI      A4          484 DPI
  5 × 7 in     800 DPI      11 × 14 in  364 DPI
  8 × 10 in    500 DPI      16 × 20 in  250 DPI
  A3           342 DPI      20 × 30 in  200 DPI

Every size up to A3 is well above 300 DPI, and even a 20 × 30 inch print is 200 DPI, which is still good.

A Screen-Sized Image

A 1920 × 1080 image, the size of a Full HD screen or a video frame, has only about 2 megapixels. At 300 DPI it prints at 6.4 × 3.6 inches. It reaches about 270 DPI on a 6 × 4 inch print, which still looks good, but an 8 × 10 print drops to about 135 DPI and will look soft up close. Screenshots and video stills are best kept to small prints.

Megapixels for Common Prints

Working backwards, a print size times the DPI gives the pixels needed. An 8 × 10 inch print at 300 DPI needs 2400 × 3000 pixels, about 7.2 megapixels. A 12 megapixel phone photo of 4000 × 3000 pixels, cropped to the 5:4 shape of an 8 × 10, keeps 3750 × 3000 pixels and gives about 375 DPI, comfortably enough.

  4 × 6 in at 300 DPI     1200 × 1800    2.2 MP
  5 × 7 in at 300 DPI     1500 × 2100    3.2 MP
  8 × 10 in at 300 DPI    2400 × 3000    7.2 MP
  16 × 20 in at 300 DPI   4800 × 6000   28.8 MP

Print Shapes and Cropping

Cameras usually shoot at 3:2 or 4:3, but many standard print sizes have different shapes: 8 × 10 is 5:4, 5 × 7 is 7:5, and A sizes are about 1.41:1. To fill the paper, part of the longer side is cropped off. The calculator works out the DPI on the side that limits the print, so the figures stay reliable even after that crop, but you should check that nothing important sits near the edges of the frame.

Viewing Distance

Required resolution falls the further away a print is seen. A photo in an album is held at 30 cm and needs about 300 DPI. A framed print on a wall, seen from a metre or two, looks fine at 150 to 200 DPI. Large banners and billboards, seen from across a room or a street, can use 20 to 50 DPI and still look sharp from where people stand.

Choosing a Print Size for a Frame

Frames are sold by the size of the picture they hold, and often come with a mount, a card border that sits inside the frame. A 16 × 20 inch frame with a mount might hold an 11 × 14 print, and a 12 × 16 frame an 8 × 10. Decide the print size first from the pixels available, then choose a frame and mount to suit. A mount also gives a little freedom with shape: the window can be cut to match the photo exactly, so nothing needs to be cropped to fit a standard paper size.

Printing From Old or Downloaded Images

Pictures saved from social media, websites and messaging apps are usually resized to around 1,000 to 2,000 pixels on the long side to save data. That is plenty for a screen but limits prints to small sizes. A 1080 × 1080 image, a common size for posts, prints at only 3.6 × 3.6 inches at 300 DPI, or 7.2 inches square at 150 DPI. If you want a large print, go back to the original file from the camera or ask the photographer for the full-resolution version.

Understanding Your Result

The headline is the print size in inches at the DPI you chose.

The centimetre line gives the same size in metric units.

The megapixels are width × height ÷ 1,000,000.

The standard sizes line lists the DPI at common print sizes, marked with a tick at 300 DPI or more, "good" from 200, "fair" from 150 and "low" below that.

The poster line shows the size possible at 150 DPI.

When Should You Use This Calculator?

Use it before ordering prints, canvases, photo books or posters.

Use it to pick the right frame size for a photo.

Use it to decide whether a phone photo is good enough for a large print.

Use it when designing printed materials to check that images will not look pixelated.

Common Mistakes

Ignoring the crop. Standard sizes rarely match the photo's shape, and cropping lowers the pixels available.

Using the file's stored DPI as a limit. The DPI field in a file is only a suggestion; the pixels decide the real print size.

Demanding 300 DPI for posters. Large prints seen from further away need much less.

Printing screenshots large. Screen-sized images have few pixels and only suit small prints.

Enlarging before printing. Upscaling adds no real detail; the print will look the same or softer.