Print-on-demand · pre-upload check
Stop waiting hours for a rejection that just says "resolution too low". Printful, Printify, Redbubble and Merch by Amazon each enforce four hard numbers. This checks all four at once: effective print DPI, dimensions, file size, transparency.
🔒 Nothing is uploaded. Every check runs in your browser — which also means your unreleased designs never touch a third party.
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.
The 300 DPI in your file properties is metadata. Anyone can change it to any number, and it will not add a single pixel. What decides sharpness is pixels divided by print-area inches — an 800px-wide file printed across 15 inches is 53 DPI, no matter what the tag says. That second number is the one platforms enforce.
For years Merch by Amazon required artwork at exactly 4500 × 5400 pixels, and half the tutorials online still say so. Its current design editor accepts anything above 485 × 485 and scales to fit. The 25 MB ceiling is still real and still written down. Checking against the old rule would fail files Amazon accepts, which is a worse error than missing one.
Paid exports centre the artwork on a transparent canvas at each platform's required size, and compress under a hard ceiling by reducing colour depth rather than dimensions. Nothing is ever enlarged — a file upscaled to pass a dimension check still prints soft, which is exactly the failure this tool exists to catch.
None of the four platforms accepts WebP. Redbubble is stricter still — JPEG and PNG only, no SVG and no PDF. Design tools now export WebP by default in several places, so this gets people who did everything else right. PNG is the only format all four take, and the only one of those that keeps a transparent background.
Plenty of design files look like they have a white background when that white is opaque pixels rather than an alpha channel. Printed on a dark shirt it becomes a white box, and no platform stops you at upload. You find out from the review.
Not from forum threads or guesswork. Every value maps to a platform's own upload documentation.
The verdict is plain arithmetic: pixels divided by print-area inches. No black-box model, and the same file always gives the same answer.
This site shows no user designs. Your file never leaves your device, so there would be nothing to show.
Everything for a single file is free forever — checking it, fixing it, downloading it. It all runs in your browser and costs us nothing to serve, so charging for it would mean charging you for your own CPU. What the paid plan sells is volume: doing the same thing to a hundred files at once.
$0forever
$12.99per month
$99per year
No free trial, and no refunds for a period already started — cancel instead, from [your account](/account), and you keep access until the period you paid for runs out. Charged something you never signed up for, or billed twice? Write to us and we will put it right.
Cancel any time — access runs to the end of the period you paid for.
DPI means nothing without a size. The number in your file properties is metadata; what platforms calculate is pixels divided by print-area inches. An 800px-wide file printed across a 15-inch area is 53 DPI regardless of the tag. Change the tag and the pixel count stays exactly the same.
A transparent PNG around 4500 × 5400 carrying any gradient, grain or photographic texture typically lands between 30 and 60 MB, against a written 25 MB ceiling. You now have three levers rather than one: trim the empty transparent margin (Amazon asks for this anyway — it is what their centring tools measure), reduce colour depth, or scale down, since the exact-size rule was dropped and anything above 485 × 485 is accepted. This tool re-encodes and reduces colour depth for you; it never enlarges.
No. Every check runs through the browser Canvas API on your own machine. You can disconnect from the network and run a check to confirm it.
No, and you should not want any tool to. Missing pixels means the information was never captured; upscaling algorithms invent plausible detail. It can look fine on screen and still print soft on fabric. Re-export from the source file instead.
There are none on single-file checks, and no account is needed. Paid plans exist for batch work: dozens of files at once, auto-fix, multi-platform export. Because the free checks run entirely in your browser, they cost us nothing, so they can stay free.
Cancel from your account page: enter the email you paid with, open the link we send you, and cancel in two clicks — no email to us, no questions. Access then runs to the end of the period you already paid for, and nothing further is charged. We do not refund a period that has already started, so cancelling before the next renewal is what stops the money. If you were billed twice, charged for something you did not sign up for, or the paid features never worked for you, write to us and we will put it right.
We track platform changes, but there can be a lag. Every platform spec page says the same thing at the bottom: check the official documentation before an upload that matters.