Before you hit “send to print”
Check your files before the printer does.
Preflight is a small set of free tools that catch the mistakes that get files rejected or come back blurry: low resolution, wrong colour mode, missing bleed. Most checks run in your browser. The optional CMYK converter is the only tool that sends a file to the server, and it processes it in memory only.
The tools
8 live · 8 plannedDPI Checker
Upload an image and your intended print size to see the exact DPI and whether it's sharp enough to print.
Print Size Calculator
See every print size your image supports at 300, 150 and 72 DPI, from wallet prints to A3 posters.
RGB to CMYK Checker
Find out if your file is in the wrong colour mode before a printer rejects it or colours shift on press.
Bleed Calculator
Work out the exact bleed, trim and safe-zone measurements for any finished print size.
Image Resolution Checker
A quick pass/fail read on whether an image file has enough pixels for the job you have in mind.
Paper Size Converter
Convert between mm, cm, inches, and points for any standard paper size, or find the closest match to a custom size.
Image Compressor & Resizer
Resize and compress a JPG, PNG, or WEBP down to a smaller file size, free -- set your target size and quality, then download.
WebP to JPG/PNG Converter
Convert WebP images to high-quality JPG or PNG format instantly, free -- 100% browser-only client-side batch processing.
Private by default
The checkers run locally in your browser using JavaScript. Only the optional real CMYK conversion sends a file to the server for in-memory processing.
Built for real print jobs
Each tool answers one specific question that comes up when preparing a file for an actual print run, not a generic image utility.
Free, and staying free
The core checkers will always be free. Paid, higher-volume tools may join alongside them later, kept clearly separate.
Why files get rejected at print
Most print rejections come down to a handful of repeat offenders: an image pulled from a website that looks fine on screen but has nowhere near enough pixels for an 8x10 print, a logo saved in RGB that shifts colour the moment it hits a CMYK press, or a flyer designed edge-to-edge with no bleed, so a millimetre of trim error leaves a thin white line around the border.
None of these are visible on a screen. A 72 DPI web image and a 300 DPI print image can look identical in a browser tab, because your monitor doesn’t care about print resolution at all. The problem only shows up once ink is on paper, which is exactly why it’s worth checking beforehand rather than after a reprint bill.
Preflight exists to catch these before a print shop does. Start with the DPI checker if you’re not sure your image will hold up at the size you want to print it -- it takes about ten seconds and runs in your browser.