DPI and Print Size Calculator

Written byOleh Soloninupdated 5 October 2026

What to work out

Width, pixels

Height, pixels

Image resolution, PPI

Pixels per inch of the print. Not the printer's DPI, which counts its ink dots.

Result

Print size50.8 × 33.9 cm
Size in pixels6000 × 4000
In inches20 × 13.33″
Megapixels24
PPI300
Quality
Whether that density is enough is best checked with a test print from the distance it will be viewed at

Pixels divided by density

Turns pixels into printed centimetres at a given resolution, and answers the reverse question of how many pixels a given format needs.

A file has no physical size: pixels only become centimetres in combination with a print resolution. The same photograph at 6000 pixels across gives twenty inches at 300 DPI and forty at 150.

Which is where the choice of density comes from: 300 DPI for a print held in the hand, 150 for a poster on a wall, and 72 or less for a banner on a building. The further away the viewer, the fewer pixels per inch are worth printing.

How to use

Enter the image size in pixels.
Set the image resolution for print in pixels per inch (PPI). That is not the printer's DPI, which counts its ink dots.
Read the physical print size in centimetres and inches.
Read the quality note: it depends on viewing distance as much as on DPI.

One file at different print densities

Each row is a run of this calculator for a 6000 × 4000 image — 24 megapixels. Only the density changes.

Size is inversely proportional to density: double the DPI and the print halves. Hence the rule people forget — 300 DPI is for a photograph held in the hand, while a poster on a wall is fine at 150, because from a metre and a half the eye cannot tell.

Runs of this calculator for a 6000 × 4000 image.
Density	Print size	In inches	Verdict
150 DPI	101.6 × 67.7 cm	40 × 26.67″	poster: clean from half a metre
240 DPI	63.5 × 42.3 cm	25 × 16.67″	poster: clean from half a metre
300 DPI	50.8 × 33.9 cm	20 × 13.33″	photographic quality
600 DPI	25.4 × 16.9 cm	10 × 6.67″	photographic quality

What this calculator shows

The print size in centimetres and inches at your chosen DPI
The reverse: the pixel count a given format needs
A quality verdict — photograph, poster or banner

What to keep in mind

The calculation ignores cropping to format: if the file's proportions differ from the paper's, part of the frame goes under the knife.
Interpolation in an editor adds pixels but not detail, so a file cannot be 'stretched up' to 300 DPI in any meaningful sense.

FAQs

How many pixels for an A4 print?

A4 is 21 × 29.7 cm, or 8.27 × 11.7 inches. At 300 DPI that needs 2480 × 3508 pixels, about 8.7 megapixels.

What does 300 DPI mean?

Three hundred dots per inch — the density at which individual dots stop resolving at arm's length. It is the standard for photographic and commercial printing.

Can I print at a lower DPI?

Yes, if the print will be seen from a distance. At 150 PPI a 6000 × 4000 image prints at 101.6 × 67.7 cm; whether that is good enough from your viewing distance is best checked with a test print.

Does the DPI tag in a file matter?

The number in the metadata adds no pixels or detail, but it can set the default print size where software uses it. How much detail reaches the paper depends on the pixel count.

Where does 300 DPI come from?

From the distance a photograph is held at — around thirty centimetres. That is a common rule of thumb rather than a guarantee: the further away a print is viewed, the lower the resolution it needs, so a poster seen from two metres gets by on far less. Judge a proof at the intended distance.

Can I raise the DPI to improve the print?

No. DPI is not a property of the file but a way of spreading the pixels you have across paper. The only ways to raise it are to print smaller or to reshoot at a higher resolution.

Worked example

A frame from a 24-megapixel camera

Input: 6000 × 4000 pixels at 300 DPI

Output: 50.8 × 33.9 cm, which is 20 × 13.3 inches

Note: A little over A3. The same file at 150 DPI makes a metre-wide poster that looks flawless from a metre and a half away.

Useful links

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DPI and Print Size Calculator

Result

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