Home / Required Resolution Calculator

Required Resolution Calculator

Find the pixels you need for a given print size.

Updated July 2, 2026

Details

Print width (inches)

Print height (inches)

Target DPI

Results

Pixels needed -

Width needed -

Height needed -

Megapixels needed -

Print size = pixels ÷ DPI.

Things To Know Before You Order More Pixels Than You Have

Camera spec sheets quote megapixels at native resolution. Cropping before you print removes pixels permanently, so recheck the cropped dimensions, not the camera's rated output.
Upscaling software can push a file over the pixel target this tool calculates, but it cannot recover detail the sensor never captured in the first place.
A phone photo can clear the pixel-count bar on paper and still look softer than a dedicated camera file at the same megapixel figure, because sensor size and lens quality affect real sharpness too.
Viewing distance changes how strict the target needs to be. A banner read from across a room can use a lower DPI target than a print held in your hands.

How Is Required Resolution Calculated From Print Size And DPI

Multiply the print width in inches by the target DPI, then multiply the print height the same way. The two results are the pixel dimensions the file needs; multiply them together and divide by a million for megapixels.

The fields above default to a 20 × 30 in print. At 300 DPI, the setting most labs use for photo-quality output, that works out to 20 × 300 = 6,000px wide and 30 × 300 = 9,000px tall, about 54 megapixels, more than most single-shot cameras deliver without stitching multiple frames together.

Drop the same 20 × 30 in print to 150 DPI, the tier common for posters viewed from a few feet back, and the requirement falls to 3,000 × 4,500px, about 13.5 megapixels, well inside range for most phone cameras. At 72 DPI, meant for screens rather than paper, the same print only needs 1,440 × 2,160px, about 3.1 megapixels. Push to 600 DPI for archival work instead and the requirement jumps to 12,000 × 18,000px, 216 megapixels, beyond what almost any single consumer camera can produce.

What A 20 By 30 Print Needs At Each Setting

Using this tool's own default print size, here is the pixel requirement at each DPI option in the dropdown:

DPI setting	Pixels needed	Megapixels
600 DPI	12,000 × 18,000 px	216.0 MP
300 DPI	6,000 × 9,000 px	54.0 MP
150 DPI	3,000 × 4,500 px	13.5 MP
72 DPI	1,440 × 2,160 px	3.1 MP

Each row is the same 20 × 30 in print multiplied by the DPI shown, computed directly from the formula above.

Good to know

FAQs

How many pixels do I need to print?

Multiply each print dimension (inches) by your target DPI. 20×30 in at 300 DPI needs 6000×9000 px.

How many megapixels for a 16×20 print?

About 28.8 MP at 300 DPI (4800×6000).

Can I upscale a small image?

Software upscaling helps a little, but it can’t add true detail.

What DPI for large posters?

150 DPI is often fine for posters viewed from a distance.

Why does my phone photo look soft when large?

Phone images may lack the pixels for big prints at 300 DPI.