What DPI do you need for printing?

By Check Before Submit · Updated 3 October 2026.

Aim for about 300 pixels per inch at the printed size, and treat anything under about 150 as a likely problem. These are common print-shop figures, not a standard, so your printer's number wins. Amazon KDP asks for images of at least 300 DPI and recommends staying at or under 600.

DPI, PPI, and the number stored in the file

PPI is pixels per inch: how many of the image's pixels land on each inch of paper. Adobe's Photoshop help describes resolution as the number of pixels per inch for print quality, and says resampling adds or removes pixels to resize an image. DPI is the dots per inch a printer lays down. People use the two words interchangeably, and for the question "is my image big enough?" the number that matters is pixels per inch at the printed size.

Many image files also store a DPI value in their metadata. That value only suggests a default print size to some programs. It does not make an image sharper or blurrier. A 4000 × 3000 pixel photo tagged 72 DPI prints at 300 PPI when it is 13.3 × 10 in, and a 4000 × 3000 pixel photo tagged 300 DPI prints at 72 PPI if you stretch it to 55.6 × 41.7 in. The pixels are the same in both cases.

The one calculation

Effective PPI = image pixels ÷ printed inches, measured along the same side.

Take a photo that is 3000 pixels wide:

Printed width	Effective PPI
6 in	500
10 in	300
12 in	250
20 in	150
30 in	100

The same photo is excellent at 6 inches wide and soft at 30. Nothing about the file changed; only the size it is asked to cover.

How many pixels do you need?

Work backwards from the size you want to print. Pixels needed = printed inches × PPI.

Print size	At 300 PPI	At 150 PPI
4 × 6 in	1200 × 1800 px	600 × 900 px
5 × 7 in	1500 × 2100 px	750 × 1050 px
8 × 10 in	2400 × 3000 px	1200 × 1500 px
A4, 210 × 297 mm	2480 × 3508 px	1240 × 1754 px
A3, 297 × 420 mm	3508 × 4961 px	1754 × 2480 px
Poster, 24 × 36 in	7200 × 10800 px	3600 × 5400 px

What target to use

Job	Typical target	Where the figure comes from
Photos, flyers, brochures, documents	300 PPI target; below 150 PPI is a likely problem	Common print-shop practice. These are the working values behind our General print profile, not a published rule.
Paperback book interior (Amazon KDP)	At least 300 DPI; 600 recommended as a maximum	KDP Help, read 3 October 2026.
Posters and large format	Around 150 PPI target; below 100 PPI is a likely problem	Our working values for large prints viewed from a distance. Large-format printers vary: some ask for less, some for 300.

The poster row exists because a print that is viewed from further away does not need as many pixels per inch. It is a rule of thumb. If your printer states a figure for your product, use that one.

What the checks report

We ran one test image, 3000 × 2000 pixels, through the DPI Checker at several print sizes using the General print profile (300 PPI target, 150 PPI minimum). It is a generated test image, so only its size matters.

Print size	Effective PPI	Result	What the report says
6 × 4 in (152 × 102 mm)	500	Passed	At or above the 300 PPI target.
10 × 8 in (254 × 203 mm)	250	Review	Below the target. About 3000 × 2400 px needed. The shape differs, so filling the print area crops about 17% of the image.
A4 (297 × 210 mm)	242	Review	Below the target. About 3508 × 2481 px needed.
A3 (420 × 297 mm)	171	Review	Below the target but above the 150 PPI minimum. About 4961 × 3508 px needed.
24 × 36 in (914 × 610 mm)	83	Fix	Below the target and below the 150 PPI minimum. About 10800 × 7200 px needed.

Checked as a poster instead, with the Poster profile (150 PPI target, 100 PPI minimum), the same image at 24 × 36 in still reports Fix at 83 PPI, and the report says it would need about 5400 × 3600 pixels.

Two details in that table are worth understanding. The 10 × 8 in row also reports an aspect-ratio difference: the photo is 3:2 and the print is 5:4, so you either crop part of the image or leave margins. And the A3 row shows why "Review" exists. At 171 PPI the image is below the usual target and above the minimum, which is a judgement call about the subject and the viewing distance, not an automatic failure.

Why enlarging in software does not rescue it

Resizing an image to more pixels adds pixels, not detail: in Adobe's words, resampling adds or removes pixels. The software guesses values between the ones it has, which can make edges look smoother but does not recover information that was never captured. If a photo is too small for the size you need, the reliable fixes are to use a larger original, to print smaller, or to ask your printer what they advise for that job.

What a resolution check cannot tell you

It counts pixels against the printed size. It does not measure focus, motion blur, noise or compression damage, so a 300 PPI image can still look poor, and a sharp image at 200 PPI can look fine. Inside a PDF, the effective PPI of each placed image depends on how big it was placed in the layout, and the same image can be fine on one page and too small on another. For that, a PDF check reports every placed image separately.

What to do next

Decide the printed size first, calculate the pixels you need from the table above, and compare with what you have. If you only have an image and want to know how large it can go, Osmanth Image, a separate site, has a free Can I print this image? tool for that question. Then check the file. Resolution is only one of the things a printer cares about: see How much bleed do you need for printing? for page size and trimming, and PDF fonts not embedded: what it means and how to fix it for the other common reason a PDF comes back. The checks on this site run in your browser and say plainly what they did not inspect: how it works.

Sources

Amazon KDP Help: Paperback submission guidelines (read on 3 October 2026)
Adobe Photoshop Help: Set image size and resolution (page last updated 23 February 2026) (read on 13 October 2026)

Figures taken from these sources are quoted as written on the date shown. Your printer's own specification always comes first.