Useful tools.
Private files.

What we make

Local file tools convert, inspect and organize images, PDFs, DOCX, EPUB and text files without a server upload. Production calculators answer specific questions such as whether an image is large enough, how labels fit on a sheet or how a book cover spread is estimated. The field guides explain the decisions behind those checks: resolution, bleed, paper, color and file formats.

Why the site works locally

File Preflight processes selected files inside your browser. Decoding, conversion and report generation happen on your device. Closing the processing tab ends that working session; files you downloaded or saved remain on your device until you remove them. This makes it possible to try a known sample before using a confidential document.

Editorial standards

Our editorial approach is to show inputs, formulas and limitations so readers can check a result. The bleed guides have regression checks that compare their numerical tables with the calculator. Other explanatory content still needs editorial review: passing software tests does not prove that every sentence or supplier-specific recommendation is correct.

Every guide carries a publication or update date and links to the underlying tools so you can reproduce the result with your own file. Where a value depends on a supplier — paper caliper, bleed allowances, carrier divisors, platform templates — the guide says so, and the supplier’s current specification always outranks our example values.

Methods and accountability

File Preflight is an independent software project, not a print laboratory or a certification service. We publish formulas and limitations so you can decide whether a result fits your job. Our test files and methods document reproducible inputs, expected outputs, automated check coverage and known gaps. A numerical result is not a guarantee of production quality.

We do not claim professional accreditation or independent laboratory testing. Printer and publisher requirements take precedence over the general planning advice on this site.

How corrections work

Use the contact and corrections page to report a tool or guide issue. Include the page URL, non-sensitive inputs, expected and actual results, and the conflicting source specification. Do not send confidential artwork or customer documents. Material corrections are dated on the affected guide and reproducible cases are added to the test bench.

Privacy by design

Calculations and file processing run locally in your browser. File Preflight does not require an account and does not receive the files or values you select. Optional analytics records page views and tool actions — not filenames, artwork or calculator inputs. The full detail lives in the privacy policy.