What resolution for an A3 (297 × 420 mm) print at 150 DPI?

An A3 (297 × 420 mm) print at 150 DPI needs 1,754 × 2,480 pixels, or 4.3 megapixels. A 12 MP phone photo (4,032 × 3,024) prints at up to 20.16 × 26.88 in at 150 DPI: enough for A3 (297 × 420 mm) without upscaling.

Last updated 2026-10-05

Pixels you need

Pixels: 1,754 × 2,480
Print size: 11.69 × 16.54 in (29.7 × 42 cm)
Megapixels: 4.3

150 DPI is the usual floor for posters viewed from one to two metres away.

Will your image be big enough?

A 12 MP phone photo (4,032 × 3,024) prints at up to 20.16 × 26.88 in at 150 DPI: enough for A3 (297 × 420 mm) without upscaling.
A 1024 × 1024 AI image (1,024 × 1,024) prints at up to 6.83 × 6.83 in at 150 DPI. It needs 4× to cover A3 (297 × 420 mm), on Pro and still on your device.
A 1920 × 1080 screenshot or video frame (1,920 × 1,080) prints at up to 7.2 × 12.8 in at 150 DPI. It needs 2× to cover A3 (297 × 420 mm), which is free.

Calculate for your image

Enter your image size. The upscale button updates to the scale you need.

A3 (297 × 420 mm) at other resolutions

DPI	Pixels	Megapixels	Good for
300 DPI	3,508 × 4,961	17.4	Photos, close viewing
240 DPI	2,806 × 3,969	11.1	Inkjet, wall prints
200 DPI	2,339 × 3,307	7.7	Large prints
150 DPI	1,754 × 2,480	4.3	Posters
100 DPI	1,169 × 1,654	1.9	Banners

How to prepare the file

Crop your image to the 11.69 × 16.54 shape so the lab does not cut anything off.
Compare your pixels with 1,754 × 2,480. The calculator above does it for you.
Upscale with the smallest scale that reaches the size, then resize to the exact pixels.
Export PNG, or JPG at quality 95, and order the print at this size.

Questions

How many pixels do I need for an A3 (297 × 420 mm) print at 150 DPI?

1,754 × 2,480 pixels: 11.69 × 16.54 inches multiplied by 150 dots per inch, rounded to whole pixels.

Is 150 DPI good enough for A3 (297 × 420 mm)?

150 DPI is the usual floor for posters viewed from one to two metres away.

Can a phone photo be printed at A3 (297 × 420 mm)?

Yes. A 12 MP photo of 4032 × 3024 already has more than 1,754 × 2,480 pixels once cropped to the print shape.

What does DPI mean for a digital file?

Dots per inch is how many image pixels land on each inch of paper. The pixel count is what matters: the DPI field saved in a file does not change the image, the printer scales the pixels to the paper size.

Does upscaling add real detail for printing?

It adds plausible detail: sharper edges and texture instead of the soft blur of ordinary resizing. It cannot recover detail the camera never captured, such as text too small to read.