Inches to Pixels Calculator

Sizing a canvas before you start

Designing for print means setting the document size in pixels correctly at the start, because scaling up afterwards loses quality that was never captured.

The calculation is physical size times resolution. A 5 by 7 inch print at 300 DPI needs 1500 by 2100 pixels. An A4 flyer needs 2480 by 3508.

Getting this wrong at the start is expensive to fix. A design built at screen resolution and then needed at print size has to be rebuilt or upscaled, and neither is a quick correction.

Adding the bleed

Anything printing to the edge needs bleed: artwork extending past the trim line so that cutting tolerance does not leave a white edge.

Standard bleed is 3 millimetres in most of the world and 0.125 inches in the US. That is added to every edge, so an A4 document with bleed is 216 by 303 millimetres rather than 210 by 297.

In pixels at 300 DPI that is 2551 by 3579 rather than 2480 by 3508. Setting up the canvas without bleed and adding it later means extending the artwork, which is straightforward for a background and impossible for a photograph that was cropped exactly to size.

Vector where you can

The whole resolution question disappears for vector artwork, which is defined mathematically and renders at whatever resolution the output device uses.

Logos, type, line art and illustration should be vector wherever possible. The same file prints on a business card and on a vehicle wrap with no loss.

Photographs cannot be vector and everything around them can. A design where the photograph is the only raster element can have its type and graphics stay perfectly sharp at any size, which is why layouts are assembled in vector applications and photographs placed into them rather than the reverse.

Colour mode, which belongs in the same setup

Setting up a print document means choosing CMYK rather than RGB, and doing it at the start rather than converting at the end.

The reason is gamut. RGB can express colours that CMYK inks cannot reproduce, particularly saturated blues, greens and oranges. Designing in RGB and converting at the end produces a print that is duller than the screen showed, and the disappointment is entirely predictable.

Working in CMYK from the beginning means the screen shows approximately what the print will do. It is less vivid to work with and it removes the conversation where a client asks why the printed piece does not match what they approved.

Common sizes worth having to hand

Business cards vary by region: 85 by 55 millimetres in the UK and Europe, 3.5 by 2 inches in the US. At 300 DPI with bleed those are 1039 by 720 and 1088 by 638 pixels.

A-series doubles predictably: A6 at 105 by 148, A5 at 148 by 210, A4 at 210 by 297, A3 at 297 by 420, each millimetre figure. US letter is 8.5 by 11 inches, or 2550 by 3300 pixels at 300 DPI.

Roll-up banners and large format vary by supplier and are usually specified in millimetres at a lower resolution, commonly 100 to 150 DPI at final size, because the viewing distance permits it and the file would otherwise be unmanageable.

The other setting worth fixing at the start is the colour profile rather than merely the colour mode. CMYK is not one thing: a document set to a generic profile and one set to the printer's actual profile will separate the same colours differently, and the difference is visible in rich blacks and in skin tones. Asking a supplier which profile they want takes one email and it removes an entire class of surprise at the proofing stage.