Sumcheck

PDF & documents → Markdown, checked

100% on-device · no uploads, ever

Chrome Web Store listing: in review — the install link will appear here when it is live.

What it does

Sumcheck is a Chrome extension that converts documents into clean Markdown, HTML, plain text or structured JSON — without sending them anywhere. PDFs (including scans, read with on-device OCR), Word, Excel, PowerPoint, EPUB, images, web pages, and a dozen more formats. Everything runs inside your browser: no accounts, no per-page charges, no telemetry, zero network requests at runtime.

It tells you what it is unsure about

Most converters hand you text and leave you to trust it. Scanned documents are where that gets expensive: a $ misread as a 3 turns $40.00 into 340.00, and the result looks perfectly reasonable.

Sumcheck checks its own work and marks what it cannot vouch for:

currency columns where one amount lost its $
line items that do not add up to the stated total
a prominent total that matches nothing else on the page
words that are not words — a confident inchided for "included"
regions of a page OCR could not read at all

Every flag is written where a reader will see it. Nothing is ever silently rewritten.

Open, and open about its limits

Sumcheck is open source under the Apache License 2.0, and its conversion quality is measured against a ground-truth corpus of real scanned documents rather than asserted. The "no network requests" claim is a property of the code, not a promise — read the source or inspect the package.