Print-on-Demand Design Size Guide (Every Product)

The short version: make your files at 300 DPI for the size each product prints, which for most items means a long edge somewhere between 3,000 and 5,400 pixels. Shirts need the most, stickers the least, and mugs and posters sit in between. I keep a cheat sheet pinned because every product has a different print area, and uploading a file that’s too small is the fastest way to get a quality warning or a blurry product. Here’s the whole table, with the math, so you can stop guessing per product.

The one rule that covers everything

Pixels equals inches times DPI. That’s the whole guide in one line. If a product’s print area is 12 inches wide and you want 300 DPI, you need 3,600 pixels of width. Suppliers like Printful and Printify both treat 300 DPI as the ideal and 150 DPI as the rough floor, so anywhere in that band prints fine. Below 150 and edges go soft. Above 300 and you’re just making a bigger file the printer ignores.

Everything below is just that formula applied to each product’s real print area.

The size table I actually use

These are practical targets pulled from Printful and Printify product specs. When suppliers publish a specific number, I use theirs; otherwise I use the print area times 300.

Product	Typical print area (inches)	300 DPI target (pixels)	Format
T-shirt, standard front	12 x 16	3,600 x 4,800	Transparent PNG
T-shirt, full front	15 x 18	4,500 x 5,400	Transparent PNG
Left chest / pocket	4 x 4	1,200 x 1,200	Transparent PNG
11oz mug wrap	~9 x 3.7	~2,700 x 1,100	PNG
Die-cut sticker	3 x 3	900 x 900	Transparent PNG
Poster, small	12 x 18	3,600 x 5,400	JPG or PNG
Poster, 18 x 24	18 x 24	5,400 x 7,200	JPG or PNG

A few of these deserve notes, because the raw number hides a catch.

Shirts

Shirts need the biggest files because you view them up close and the print area is large. Printify recommends 4,500 x 5,400 px for a full-front print, which is 15 x 18 inches at 300 DPI. A standard front print is closer to 12 x 16. If you build every shirt design at 4,000 to 4,500 pixels on the long edge, you cover both placements and never have to recheck. Use transparent PNG so the shirt color shows through instead of a white box. The DPI side of shirts gets its own breakdown in what DPI you need for t-shirt printing if you want the reasoning, not just the number.

Mugs

Mugs trip people up because the print “wraps” around the cylinder. An 11oz mug has a print area roughly 9 inches wide by about 3.7 inches tall, so 300 DPI lands around 2,700 x 1,100 pixels. Design it as a long horizontal strip, not a square. The two spots near the handle don’t print, so keep important elements toward the center of the wrap. A square logo centered on a mug template wastes most of the canvas.

Stickers

Stickers are forgiving on file size and brutal on the cut line. A 3 inch die-cut sticker only needs 900 x 900 pixels at 300 DPI, which almost any AI generator gives you without upscaling. The thing that breaks stickers isn’t resolution, it’s the transparent background and the contour. You want a clean transparent PNG with a bit of padding so the white border can follow the shape. A sticker with a faint white halo around it usually means a sloppy cutout, not a low DPI.

Posters

Posters are the exception to “always 300 DPI.” Because people view a poster from a few feet away, 150 DPI is genuinely acceptable for larger sizes, and it keeps the file from getting huge. An 18 x 24 poster at 300 DPI is 5,400 x 7,200 pixels, which is a heavy file. At 150 DPI it’s 2,700 x 3,600 and still looks sharp on a wall. For small art prints you’ll hold in your hand, stay at 300. For big wall posters, 150 to 200 is fine.

Where AI design sizes bite you

Here’s the practical problem if you generate art with AI. A lot of tools output 1,024 or 2,048 pixels by default. That’s plenty for a sticker or a pocket print and too small for a full-front shirt or a poster at 300 DPI. You’ll either print smaller than you wanted or upscale, and upscaling a soft image just makes a bigger soft image. I go through which upscalers actually hold up in how to upscale an image for printing.

This sizing headache is why I made LzyPOD output up to 4K with a transparent background by default. Generating big from the start means the same file works for a sticker and a full-front shirt, and I never have to regenerate because a design was too small for the product I wanted.

How to use this without memorizing it

Don’t memorize the table. Memorize the formula and one safe default: build at a 4,000 pixel long edge, transparent PNG, sRGB. That single file is oversized for stickers and mugs (which is fine, the printer downsamples), and correct for shirts and most posters. When you genuinely need a giant poster, scale up to the 5,400 or 7,200 figure for that specific size.

Before you create a product, open your file and check its actual pixel dimensions against the row above. That ten-second check has saved me from listing more blurry products than I’d like to admit. If you’re also wondering whether to deliver art as PNG or vector for any of these, that’s a different decision worth getting right per product.