How do I calculate DPI for printing?

Divide the width of the image in pixels by the width of the print in inches. A photo 3,000 pixels wide printed 10 inches wide comes out at 300 DPI. Do the same with the height: if the two numbers differ, the image and the print have different proportions, and the calculator shows the DPI both when the image fills the print and when it fits inside it. Working in centimeters, divide the pixels by the centimeters and multiply by 2.54.

What DPI do I need for a good print?

The common guidance from commercial printers is 300 DPI for anything seen up close, like photos, business cards, flyers and brochures, about 150 DPI for posters seen from a few feet away, and around 100 DPI or less for banners and signs read from across a room or a street. The farther away people stand, the fewer pixels per inch they can see. If your printer gives a number for the job, use theirs.

Is this a mouse DPI calculator?

No. This calculator is for images and printing: how many pixels go into each inch of paper. Mouse DPI is a gaming setting that measures how far the pointer moves for each inch the mouse travels, and converting sensitivity between games is a different calculation that this page does not do.

Can I use centimeters or millimeters?

Yes. Inches are the default, and the switch above the print size changes every field and result to centimeters or millimeters, converting what you already typed. DPI itself stays per inch, because that is how printers and image editors use it, and the result also shows the same density in pixels per centimeter.

How do I check the DPI of an image?

Drop the image on the calculator. It reads the size in pixels and the DPI stored in the file (the JFIF density or EXIF resolution of a JPEG, the pHYs chunk of a PNG, the EXIF of a WebP), on your device, without uploading anything. Keep in mind that the stored DPI is only a label: what decides how sharp a print looks is the number of pixels divided by the print size, which the calculator works out next to it.

What is the difference between DPI and PPI?

PPI, pixels per inch, describes an image: how many of its pixels go into each inch when it is printed or shown. DPI, dots per inch, strictly describes a printer: how many dots of ink it lays down per inch, usually several dots for each pixel. In everyday use, and in most print shops, people say DPI for both, and when you size an image for print the math is the same. This calculator works in pixels per inch and calls it DPI because that is the word you will hear.

Why does my photo say 72 DPI?

Many cameras, phones and screenshot tools write 72 DPI into the file by default, a value inherited from early screens. It does not mean the photo is low quality: a 4,000 by 3,000 pixel image stored at 72 DPI holds exactly the same pixels as one stored at 300 DPI. The only difference is the print size an app suggests when you open it. Enter the print size you want and the calculator gives the real DPI.

Will changing an image to 300 DPI make it sharper?

Not by itself. Changing the DPI number without changing the pixels only changes the print size the file suggests; the detail stays the same. Making the image bigger in pixels (resampling) does give you 300 DPI at a larger size, but the software has to invent the new pixels, so it looks smoother rather than sharper. If the calculator says your image is too small for the print, the best fix is a larger original: the camera file, the vector logo or a higher resolution export.

DPI Calculator for Print: Pixels to Inches, cm and mm

How to use the DPI calculator

The calculator answers the three questions that come up when an image meets paper. Pick one at the top and fill in what you know:

The DPI. You have an image and a print size in mind, say a 3,000 × 2,000 pixel photo on an 8 × 10 inch print. The calculator tells you how many pixels land in each inch, and whether that is enough for the job.
Print size. You have an image and want to know how big it can go. Enter its pixels and the DPI your printer asks for, usually 300, and you get the largest print at that quality, with the common sizes it covers.
Pixels. You know the print size and need to tell a photographer, a designer or an export dialog how many pixels to deliver. Enter the size and the DPI and you get the width and height in pixels.

To skip typing the pixels, drop the image on the box. The calculator reads its width and height and the DPI saved in the file, on your device. Inches are the default; switch to centimeters or millimeters next to the print size and everything converts, including what you already typed.

Searching for a mouse DPI calculator? That is a different tool. Mouse DPI measures how far the pointer moves for each inch the mouse travels, and gamers use it with in-game sensitivity. This page is about pixels on paper.

The DPI formula

DPI in this sense means pixels per inch of print. Three versions of one formula cover every case:

DPI = pixels ÷ inches: 3,000 pixels across 10 inches is 300 DPI.
inches = pixels ÷ DPI: 3,000 pixels at 300 DPI print 10 inches wide.
pixels = inches × DPI: 8 inches at 300 DPI need 2,400 pixels.

For metric sizes, convert first: one inch is exactly 25.4 millimeters, so divide millimeters by 25.4 (or centimeters by 2.54) to get inches. A4 paper is 210 × 297 mm, which is 8.27 × 11.69 inches, and at 300 DPI needs 2,480 × 3,508 pixels.

Do the sum for the width and the height separately. If the two DPI values differ, the image and the paper have different proportions: a 3:2 photo on an 8 × 10 print, for example. Then you either fill the paper and crop part of the image, which gives the lower of the two DPIs, or fit the whole image inside and leave a margin, which gives the higher one. The calculator shows both.

Print	Size	Pixels at 300 DPI	Pixels at 150 DPI
Photo print	4 × 6 in	1,200 × 1,800	600 × 900
Photo print	8 × 10 in	2,400 × 3,000	1,200 × 1,500
US Letter	8.5 × 11 in	2,550 × 3,300	1,275 × 1,650
Tabloid	11 × 17 in	3,300 × 5,100	1,650 × 2,550
Poster	18 × 24 in	5,400 × 7,200	2,700 × 3,600
Poster	24 × 36 in	7,200 × 10,800	3,600 × 5,400
A4	210 × 297 mm	2,480 × 3,508	1,240 × 1,754
A3	297 × 420 mm	3,508 × 4,961	1,754 × 2,480
US business card	3.5 × 2 in	1,050 × 600	525 × 300

These sizes are the trimmed paper. If your design runs to the edge, the printer will ask for extra bleed around it, so add their bleed to the print size before you work out the pixels.

What DPI do you need for printing?

There is no single right number. What matters is how close people will stand to the print: the farther away, the fewer pixels per inch the eye can resolve. Commercial printers give broadly the same guidance:

DPI	Good for	Seen from
300 and up	Photos, business cards, flyers, brochures, magazines, packaging	In the hand
150 to 299	Posters, wall prints, large photo prints, trade show graphics	A few feet away
100 to 149	Banners, roll-up stands, signs	Across a room
Under 100	Very large signs and billboards only	From the street

Common print guidance, as published by commercial printers such as Centex Printing (300 DPI for business cards, brochures, flyers, magazines and photographs viewed up close) and 4over4 (largest sharp print at 300, 150 and 100 DPI), both read on October 13, 2026. Your printer's own file specification always wins.

The calculator uses these bands for the verdict next to the result. Treat them as a guide, not a law: a sharp, well exposed photo at 240 DPI usually prints better than a blurry one at 300, and line art and small text show low resolution sooner than a soft landscape does.

Pixels to inches: print and screen

Converting pixels to inches has no fixed answer, because a pixel has no physical size until you decide how many go into an inch. That number is the DPI. A 1,200 pixel wide image is 4 inches wide at 300 DPI, 8 inches at 150 DPI and 16.67 inches at 72 DPI.

On screens there is one convention worth knowing. In CSS, the language that lays out web pages, an inch is defined as 96 pixels, so a 960 pixel wide element is 10 CSS inches. That is a reference size for layout, not a measurement of your monitor: phones and high resolution displays pack two or three device pixels into each CSS pixel. If you are converting for a web page or a design tool, 96 is the number to use; for paper, use the DPI of the print.

Pixels	At 72 DPI	At 96 DPI	At 150 DPI	At 300 DPI
600 px	8.33 in	6.25 in	4 in	2 in
1,080 px	15 in	11.25 in	7.2 in	3.6 in
1,920 px	26.67 in	20 in	12.8 in	6.4 in
3,000 px	41.67 in	31.25 in	20 in	10 in
4,032 px	56 in	42 in	26.88 in	13.44 in

DPI, PPI and the 72 DPI question

Strictly, PPI (pixels per inch) describes an image and DPI (dots per inch) describes a printer, which lays down several tiny dots of ink for every pixel. In practice nearly everyone, print shops included, says DPI for both, and when you size an image for paper the arithmetic is identical. A PPI calculator and a DPI calculator for print do the same job. So keep three numbers apart: the pixel dimensions of the file (3,000 × 2,000 px), the effective PPI at a given print size (3,000 px across 10 inches is 300 PPI, what this page calls DPI), and the printer's own DPI, which is how finely it places ink and says nothing about your file.

Most image files also carry a DPI value in their metadata: the JFIF header or EXIF data of a JPEG, the pHYs chunk of a PNG. Phones and cameras often write 72 there by default. That number is only a suggestion for the print size an app should use when it opens the file. It does not change a single pixel: a 4,032 × 3,024 phone photo marked 72 DPI holds exactly the same detail as the same photo marked 300 DPI. When a printer asks for a 300 DPI file, what they need is enough pixels for the print size at 300 per inch, which is what the calculator checks.

That is also why changing an image to 300 DPI in an editor does not make it sharper. Changing the number alone only changes the suggested print size. Resampling, telling the editor to add pixels, makes the file bigger, but the new pixels are guessed from their neighbors, so the print comes out smoother, not more detailed. If the image is too small for the print, look for a larger original: the camera file rather than the one sent over a messaging app, or the vector version of a logo.

Getting files ready for the printer

Enough pixels is the first check on a print file, not the last. Before you send artwork to a printer, run through the rest:

Logos and text as vectors. Type and logos exported as pixels go soft at any DPI. Keep them as vectors in a PDF so they print crisp at any size, and save pixel resolution for photos.
Bleed and safe area. Anything that touches the edge of the page has to run past it into the bleed, and important content has to stay clear of the trim. Your printer's template gives the exact distances.
Color. Screens show RGB, presses print CMYK. Bright blues, greens and oranges can shift, so ask for a proof when a brand color matters. Our brand guidelines template keeps the screen and print values of each color side by side.
Size and proportions. Check that the image has the proportions of the print, or decide where to crop it, before the printer decides for you.

Methodology and limits

Formulas: DPI = pixels ÷ inches, inches = pixels ÷ DPI and pixels = inches × DPI, for the width and the height separately. Centimeters and millimeters are converted with 1 in = 2.54 cm = 25.4 mm, which is exact by definition. Pixels per centimeter are DPI ÷ 2.54.
Different proportions: When both sides of the print are given and the two DPI values differ by more than 1%, the result shows the DPI when the image fills the print (the lower value, part of the image is cropped) and when it fits inside it (the higher value, with the printed area). With one side empty, the other follows the proportions of the image.
Rounding: DPI is rounded to the nearest whole number for display; the verdict uses the unrounded value. Print sizes show two decimals in inches and centimeters and one in millimeters. Pixels needed are rounded to the nearest whole pixel, the usual convention in export dialogs (A4 at 300 DPI gives 2,480 × 3,508).
Verdict: 300 DPI and up, 150 to 299, 100 to 149 and under 100, from the common guidance published by commercial printers listed in the sources. It assumes a sharp image: the calculator counts pixels, it cannot see focus, noise or compression.
Reading an image: The file is read in your browser. Width and height come from the browser's decoder, with the EXIF orientation applied, or from the file header when the browser cannot display the format (TIFF in most browsers). Stored DPI comes from the JFIF density and EXIF XResolution and YResolution of JPEG files, the pHYs chunk of PNG, the EXIF chunk of WebP, the resolution tags of TIFF and the header of BMP. When a JPEG has both JFIF and EXIF values, EXIF is shown, as most editors do. Values stored per centimeter or per meter are converted to per inch.
Limits: The calculator does not resize or resample the image and does not change its metadata. It does not read DPI from HEIC, AVIF, GIF or SVG files (GIF and SVG have no such field). Presets are trimmed paper sizes without bleed. It does not calculate mouse DPI, eDPI or screen pixel density.

Sources

Show all 8 sources

CSS Values and Units Module Level 3, absolute lengths, W3C, for 1 in = 2.54 cm = 96 CSS pixels
NIST Special Publication 811, Guide for the Use of the International System of Units, National Institute of Standards and Technology, for the exact inch of 25.4 mm
ISO 216:2007, Writing paper and certain classes of printed matter, trimmed sizes, A and B series, International Organization for Standardization
ITU-T T.871, JPEG File Interchange Format (JFIF), International Telecommunication Union, for the density fields of JPEG files
Exif standard (CIPA DC-008), Camera and Imaging Products Association, for XResolution, YResolution and ResolutionUnit
Portable Network Graphics (PNG) Specification, pHYs chunk, W3C
DPI Calculator for Printing, Centex Printing, read October 13, 2026, for 300 DPI on items viewed up close
DPI Calculator: The Largest Size Your Image Prints Sharp, 4over4, read October 13, 2026, for the 300, 150 and 100 DPI tiers

DPI calculator for images and print

Image size in pixels

Print size

The right DPI is one check. Print-ready files are a dozen.

DPI Calculator: the complete guide