Checker
Merch by Amazon checker
All four of Merch by Amazon's hard numbers, checked at once. The file stays in your browser.
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.
Merch by Amazon: the numbers that matter
| Minimum size | 485 × 485 px — the only hard dimension rule |
|---|---|
| Recommended size | 4500 px or more on the long edge |
| Physical size | 4500 × 5400 = 15″ × 18″ at 300 DPI |
| File format | PNG, RGB, 8 bits per channel |
| File size limit | 25 MB — stated in writing |
| Typical real size | 30 – 60 MB |
| Before exporting | Trim the empty transparent margin |
How this tool calculates DPI
It ignores the DPI tag written into the file and divides the pixel count by the 15″ × 18″ print area instead — which is the figure the platform actually enforces.
Frequently asked questions
What DPI does Merch by Amazon require?
Prepare at 300 DPI across the print area. Merch by Amazon is permissive about low-resolution uploads, so the risk sits in the finished product rather than at the upload step.
Do I need an account to check a file?
No. The whole check runs in your browser — no account, no upload.