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Supported file formats and what is rejected

Content Uploader reads Excel, OpenDocument and CSV files and a ZIP of images. Which extensions work, which files are rejected, and the message each rejected file gets.

  • 3 min read
  • Updated October 13, 2026
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Content Uploader reads the file you drop from its content, not from its name. A workbook saved with the wrong extension still works, and a file with the right extension but the wrong content is refused with a message that tells you what to do.

What you can upload#

Kind Extensions Notes
Excel workbook .xlsx, .xlsm Read from the first worksheet. Macros are never run.
Excel 97 to 2003 .xls Converted to .xlsx first, in a separate step, so a damaged file cannot disturb anything else. A large file can take half a minute; if it takes too long the upload fails and asks you to save it as .xlsx.
OpenDocument spreadsheet .ods From LibreOffice, Apache OpenOffice or Google Sheets (File → Download → OpenDocument). First sheet.
CSV and text .csv, .tsv, .txt Comma, semicolon or tab separated, detected for you. UTF-8, or UTF-16 with a byte order mark.
ZIP .zip Either a ZIP of images next to the spreadsheet, or one ZIP that holds the spreadsheet and the images. See upload images in a ZIP.

The file picker offers these extensions. A file's name does not matter beyond that.

What is rejected#

File Message
A password-protected workbook This workbook is password-protected. Remove the password in Excel and upload it again. (.xls: This .xls workbook cannot be read. If it is password-protected, remove the password; otherwise save it as .xlsx and upload it again.)
An Excel binary workbook (.xlsb) Excel binary workbooks (.xlsb) are not supported. Save it as .xlsx, .ods or CSV and upload it again.
An Apple Numbers file Apple Numbers files are not supported. In Numbers, choose File › Export To › Excel or CSV.
A web page or XML file saved under a spreadsheet name This file is a web page or XML document, not a spreadsheet. Open it in Excel, then save it as .xlsx or CSV.
Any other binary file, or a damaged file This file is damaged or not a spreadsheet. Save it as .xlsx, .ods or CSV and upload it again.
A file with another extension, such as .pdf or .docx The picker does not offer it; if you force it, the upload is refused because the extension is not one of the supported ones.
A spreadsheet over 10 MB Spreadsheets must be at most 10 MB.

A refused file never starts a run and costs nothing. The file cannot be read lists every message with the fix.

How cells are read#

Workbook cells are imported as stored, not as displayed. This matters for numbers and dates; the complete rules are in text, numbers and dates. In short:

  • Numbers become plain decimals (12.5). A percentage is read as a fraction (50% is 0.5), and a currency amount without its symbol.
  • Dates become 2026-09-27 13:45:00; a date without a time is read as midnight.
  • Yes/no cells become TRUE or FALSE.
  • Formulas are not evaluated: a formula cell holds the result that was saved with the workbook.
  • Rows at the end that only hold formatting, and blank rows, are ignored.
  • Only the first worksheet is read. Comments, charts and embedded pictures are ignored, and merged cells keep the following columns in place.

ZIP files#

A ZIP may be up to 25 MB, may hold at most 2,000 files and may expand to at most 200 MB. Encrypted ZIPs, entries that point outside the archive (such as ../) and damaged archives are refused. A ZIP uploaded alone must contain exactly one spreadsheet (CSV, TSV, XLSX, XLSM, XLS or ODS; macOS's __MACOSX folders and hidden files are ignored). Details and messages: upload images in a ZIP.

Limits that apply to every file#

Spreadsheet 10 MB, at most 10,000 data rows and 100 columns, 32 KB of text in one cell, 128 KB per row, 25 MB of text per file. The same limits apply on every plan. Large files explains what to do when a file is over a limit.

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