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Formats

What is a .numbers file?

Short answer

A .numbers file is a spreadsheet created by Apple Numbers, the spreadsheet app included with macOS, iOS and iPadOS. Current files are packages built from Apple's proprietary IWA format, which Apple has not publicly documented. Numbers opens Excel and CSV files, but other programs usually need the file exported to XLSX or CSV first.

Updated

A .numbers file is the native document format of Numbers, Apple's spreadsheet app for Mac, iPhone and iPad, and also available in a browser through iCloud. It belongs to the iWork family, alongside Pages (.pages) and Keynote (.key).

How is a .numbers file built internally?

Since the 2013 rewrite of iWork, a Numbers document is a package: a bundle of files that behaves like one document. On a Mac it can be saved as a single file, which is a ZIP archive, or as a folder-style package. Inside you will find:

  • Index/ with the document data in .iwa files.
  • Data/ with images and other media.
  • Metadata/ with version and identifier information.
  • A preview image used for thumbnails.

IWA stands for iWork Archive. Each .iwa file is a stream of Protocol Buffers messages compressed with a variant of Snappy. Apple has not published a specification, so the structure is known only from reverse engineering by third parties. That is the main reason few programs read .numbers files directly. The format also changes between Numbers versions, and a file saved by a new version may not open in an old one.

How does Numbers' canvas differ from Excel's grid?

Numbers is built around a canvas, not a single grid. A sheet can hold several tables, charts, images and text boxes placed anywhere. Excel, by contrast, has one grid per sheet. When a Numbers document is exported, each table has to be mapped onto the other program's model:

  • Export to Excel lets you choose one worksheet per table or one per Numbers sheet.
  • Export to CSV or TSV can create one file per table, or combine the tables into one file.
  • Charts and images can be carried into an Excel export, but CSV holds cell values only.

Numbers also has its own function library and cell formats. Most common functions such as SUM, IF, VLOOKUP and PMT exist in both apps, but some Numbers-specific features have no direct equivalent and are converted to static values or dropped.

How do I export a .numbers file from Numbers?

On a Mac, with the document open:

  1. Choose File > Export To.
  2. Pick Excel, CSV, TSV, PDF or another format.
  3. Set the options, such as one worksheet per table, and click Next.
  4. Name the file and click Export.

Exporting does not change the original .numbers file.

How can I open a .numbers file without Numbers?

The options are covered step by step in how to open a .numbers file on Windows. In short: use Numbers for iCloud in a browser, ask the sender to export to XLSX or CSV, or try LibreOffice, which has a partial import filter that works better on older files.

What goes wrong when a .numbers file is converted?

  • Renaming .numbers to .xlsx does nothing useful. The contents are not Excel XML.
  • A CSV export keeps values only. Formulas, formatting and charts are lost, as with any CSV file (see XLSX vs CSV).
  • If you share spreadsheets with people on different platforms, saving in XLSX avoids most problems. The blog post on which spreadsheet format to use compares the choices.