File types
You can upload:
- Documents: Word (.docx), PDF (.pdf), plain text (.txt), Markdown (.md), HTML (.html)
- Data: CSV (.csv) and Excel (.xlsx); the text in cells is checked
- Images and scans: PNG and JPEG, and scanned PDFs, read with OCR (signed-in members)
- Source code: common source files; the comments and strings are checked as writing, the code itself is not
Anything you can paste as text also works without a file.
Limits
- File size: up to 25 MB per file.
- Length: up to 25,000 words in one check. A longer document is refused with a message naming the limit; split it into parts and check each.
- Minimum: a check needs a few sentences. Very short text is refused with the minimum shown.
- Free scans without an account: up to 250 words, 3 scans a day per visitor. Uploads are accepted on free scans, but scanned PDFs and images need an account.
What is not accepted
Password-protected files, files whose text cannot be extracted, and archives. If a Word or PDF file is refused, open it and copy the text into the composer instead; the check is identical.