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.
Checking one file at a time is free and always will be. Batch checking up to 100 files, one-click exports sized for every platform, and CSV reports are 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.
Merch by Amazon demands exactly 4500 × 5400 pixels and a file under 25 MB. A transparent PNG at that size routinely lands between 30 and 60 MB. This is not "make the image smaller" — it is a constrained optimisation with the pixel dimensions nailed down.
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.
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.
Single-file checks are free forever, because they run in your browser and cost us nothing to serve. Paid plans solve the "forty files at once" problem.
$0forever
$12.99per month
$99per year
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.
Merch by Amazon requires exactly 4500 × 5400 pixels and a file under 25 MB, and a transparent PNG at that size typically lands between 30 and 60 MB. The two rules genuinely conflict. This tool offers a re-encode that strips metadata and re-runs PNG compression without touching a single pixel dimension, which clears the ceiling in most cases.
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.
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.