Platform spec
Printful image requirements
Requirements are set per product and per print area — some DTG products use 15″ × 18″, which is 4500 × 5400 at 300 DPI. Density should be at least 150 DPI. Files are capped at 200 MB and 20,000 px on a side. Always check the File Guidelines tab on the specific product.
Full specification
| Dimensions | set by product and print area |
|---|---|
| Some DTG products | 15″ × 18″ = 4500 × 5400 px at 300 DPI |
| Minimum density | 150 DPI |
| Recommended working density | 300 DPI |
| Maximum file size | 200 MB |
| Maximum dimensions | 20,000 × 20,000 px |
| Authoritative source | the File Guidelines tab on each product page |
One file, several physical sizes
Printful scales a design across a garment size run, so the same file prints larger on a 3XL than on a S. A file sitting exactly at 150 DPI across the base print area therefore drops below it on the larger sizes — and nothing warns you, because the file passed when you uploaded it. The scale factors are not published, so the useful number is not a percentage but a width: how wide this file can be printed before it falls under the floor. At 4500 × 5400 that width is 30″, double the 15″ base area, which is one of the reasons to build the master at that size rather than at the minimum that passes.
Why the recommended size matters more than the DPI figure
DPI is a ratio, and a ratio without a physical size tells you nothing. Rather than remembering "it needs 300 DPI", remember this platform's recommended pixel dimensions — get the pixel count right and the DPI follows. The reverse never works: a file tagged 300 DPI with too few pixels fails everywhere.
Batch, auto-fix and exports
Everything above is free for one file at a time, and always will be. Doing it to a whole folder — batch checking up to 100 files, one zip with every platform file for every design, and a CSV report — is part of Seller.
Exports are padded and centred to each platform's size on a transparent canvas. Nothing is ever upscaled — a file enlarged to pass a dimension check still prints soft, which is the failure this tool exists to prevent.
Frequently asked questions
What size should an image be for Printful?
There is no single answer, and anyone giving you one is quoting a single product page. Printful sets dimensions per product — DTG apparel is 4500 × 5400. Check the requirement on the specific product, or build one master at 4500 × 5400 and scale down.
What is the maximum file size on Printful?
200 MB. There is also a ceiling of 20,000 pixels on a side. Going over it is one of the few things that reliably stops an upload.
Can I upload a WebP to Printful?
No. Printful accepts PNG, JPEG, PDF. WebP is not on the list at any of the four platforms, and several design tools now export it by default — so this catches people who got everything else right. Re-export as PNG.
Is 300 DPI enough for Printful?
DPI on its own is not a quantity — it only means something once you fix a physical size. Printful advises 150 DPI, measured across the 15″ × 18″ print area, which works out to 2250 × 2700 pixels. A file tagged 300 DPI with fewer pixels than that is not 300 DPI where it counts.
Will Printful reject a low-resolution file?
No. Printful publishes no density at which an upload is refused; low resolution produces a warning at most. That is the trap — the file goes through, the product lists, and the problem surfaces when a customer opens the parcel.
Does Printful need a transparent background?
Yes. Without an alpha channel the white background is treated as ink, and on a dark garment it prints as a visible white box around the artwork.
How current are these numbers?
Read off How should I prepare my print file for the best results? on 2026-10-06; that document was last updated 2026-10-06. Platforms revise specs quietly — Merch by Amazon dropped its exact-size requirement without announcing it — so check the source before an upload that matters.