DPI for Print: What 300dpi Means and How Many Pixels You Need

DPI (dots per inch) is how many image pixels land in each inch of the printed item. 300dpi means 300 pixels across every inch, about 118 per centimetre, which is enough detail for anything held in the hand: business cards, leaflets, stickers and stationery. Large items seen from further away need less: 150dpi at full size looks sharp on A1 and A0 posters and roller banners, and signs and PVC banners need at least 100dpi. To work out the pixels you need, divide the printed size in millimetres by 25.4 and multiply by the dpi.

DPI and PPI

Strictly, an image file has pixels per inch (ppi) and a printer lays down dots per inch (dpi). In everyday use, and in most software, dpi is used for both, and that is how we use it. What counts is simple: how many pixels the image has, compared with the size it will print. Our glossary entry on dpi gives the short version.

The dpi number saved inside a file means nothing on its own. A photo of 3000 x 2000 pixels is 300dpi at 254 x 169mm and 150dpi at 508 x 339mm. The pixels are the same; only the printed size changes.

How to work it out

Pixels needed = printed size in mm ÷ 25.4 × dpi

A business card with bleed is 91 x 61mm. 91 ÷ 25.4 × 300 = 1075, and 61 ÷ 25.4 × 300 = 720, so a photo filling the card needs about 1075 x 720 pixels.

Turn it round to see how big a photo can print: printed size in mm = pixels ÷ dpi × 25.4. A square image of 1080 x 1080 pixels, a common size for social media, prints at about 91mm across at 300dpi, or 183mm at 150dpi. That is fine for a business card or a sticker, and far too small for a poster.

Pixels you need for each product

Figures are for an image filling the whole artwork, including bleed, rounded to the nearest pixel.

For large signs and banners, 100dpi is the minimum:

A photo that fills only part of the design needs pixels only for the part it covers: a 50 x 50mm photo on an A5 leaflet needs about 591 x 591 pixels at 300dpi.

Which dpi for which product

The bigger the item, the further away people stand, and the less detail the eye can see. A 3 metre banner at 300dpi would make a very large file with no visible gain. Our artwork guidelines list the figures for every product.

How to check a photo's pixel size

• Windows: right-click the file, choose Properties, then the Details tab, and read the dimensions.
• Mac: open the image in Preview and choose Tools, then Show Inspector.
• Phone: most photo apps show the size under the photo's details or info.

Compare the two numbers with the table above. Check the original file: a photo sent through a messaging app or downloaded from social media has usually been made smaller.

Typing 300 into the resolution box does not add detail

Changing the resolution from 72 to 300 in an image editor, without adding pixels, either shrinks the printed size or stretches the same pixels further, so the picture prints soft. Enlarging ("upscaling") an image adds pixels but not real detail. Start with the largest original you have: the camera or phone file, or the file from the photographer or designer.

Logos and text are different. Supplied as vector artwork, such as an SVG, EPS, AI or vector PDF, they have no pixels and stay sharp at any size, so dpi does not apply to them. A logo copied from a website is usually a small raster image and prints with soft edges.

What our check does about resolution

Every upload gets a free automatic check. It estimates the resolution of the images in your file at full size and shows a warning if they fall below 250dpi on small items such as cards, leaflets and stickers, or below 100dpi on posters, signs and banners. A low-resolution warning does not stop the order: you can upload a better image, or tick to accept that the print may look soft. The check is an estimate, so look at the on-screen proof too. Our page on proofs and file checks explains each result.

Questions

What does dpi mean? Dots per inch: how many image pixels land in each inch of the printed item. At 300dpi, an inch of print holds 300 pixels across. Strictly an image file has pixels per inch (ppi), but most people and most software say dpi for both.

Why is 300dpi the standard for print? At 300dpi the pixels are too small to see at reading distance, so photos on cards, leaflets and stickers look smooth. Large items are seen from further away, so 150dpi at full size looks sharp on A1 and A0 posters and roller banners, and signs and banners need at least 100dpi.

How many pixels is 300dpi for A4? An A4 page with 3mm bleed is 216 x 303mm, which needs about 2551 x 3579 pixels at 300dpi. Without bleed (210 x 297mm) it is about 2480 x 3508 pixels. At 150dpi, A4 with bleed needs about 1276 x 1789 pixels.

Is 72dpi good enough for print? Only if the image has enough pixels for the printed size. The number saved in the file does not matter; the pixel count does. A 72dpi web image is usually small, often under 1000 pixels across, which is enough for a business card photo but not for a leaflet or poster.

Can I make a low-resolution image 300dpi? Not with real detail. Changing the resolution setting without adding pixels shrinks the printed size or leaves the image soft, and enlarging it adds pixels but not detail. Use the original, larger file from the camera, phone or designer, or a vector version of a logo.

What dpi do I need for a banner? At least 100dpi at the full banner size for PVC banners, and 150dpi for roller banners and anything seen close up. A 3000 x 1000mm PVC banner with bleed needs about 11850 x 3976 pixels at 100dpi. Logos and text should be vector.

Will you reject a low-resolution file? No. Our automatic check shows a warning, and you can upload a better image or accept that the print may look soft. A warning does not stop the order, but the result can only be as sharp as the image you supply.