File types · Explainer

The Numbers file (.numbers)

A Numbers file is a spreadsheet from Apple Numbers, the free spreadsheet app on Mac, iPhone and iPad: a ZIP of compressed binary archives in a format Apple doesn't document. This guide explains what's inside one, how Numbers organises tables differently from Excel, how to open one on Windows and convert it, and has free sample Numbers files to download for testing.

Sample Numbers filesPut a Numbers file online

At a glance

Full name
Apple Numbers spreadsheet
Extensions
.numbers
MIME type
application/vnd.apple.numbers
Kind
Binary: a ZIP file (or a package folder) of IWA archives, which are Snappy-compressed Protocol Buffers
Owner
Apple; the format is not publicly documented
First released
2007, with Numbers 1.0 in iWork '08; the current IWA format since Numbers 3.0 in 2013
Opens with
Numbers on Mac, iPhone and iPad; Numbers for iCloud in a browser, including on Windows
Magic number
50 4B 03 04 ("PK"), the ZIP signature, for a single-file document; a package is a folder
Structure
Sheets, each a canvas holding any number of tables, charts, text and images
Price
Numbers is free; an Apple Creator Studio subscription adds extra content and AI features

The basics

What is a Numbers file?

A .numbers file is a document from Numbers, Apple's spreadsheet app, which comes free with every Mac, iPhone and iPad and also runs in a browser as Numbers for iCloud. It holds sheets with tables, formulas, charts, text, images and comments, much like an Excel workbook, but organised differently and stored in a format only Apple's apps fully understand.

Numbers 1.0 shipped in 2007. With Numbers 3.0 in 2013, Apple moved Numbers, Pages and Keynote to a new storage format based on IWA files. That format, updated over the years, is what current versions still use: Numbers 15 is the current major version, and files saved by Numbers 15 and 14 open in either.

Three things a Numbers file is not:

  • Not an Excel file. Excel, Google Sheets and most other programs can't open .numbers files. To share with them, export to XLSX, CSV or PDF.
  • Not an open format. Apple publishes no specification. Everything known about the inside comes from reverse engineering.
  • Not always a single file. A Numbers document can also be saved as a package: a folder that a Mac shows as one file. Packages break easily when emailed or uploaded through a browser.

Anatomy

What's inside a Numbers file

A .numbers file saved as a single file is a ZIP archive. Inside are dozens of .iwa files (iWork Archive), a few property lists and preview images. Apple doesn't publish the format; what follows is the structure of our sample-workbook.numbers, decoded with the help of reverse-engineering notes from the SheetJS and numbers-parser projects.

sample-workbook.numbers (entries and first bytes)
sample-workbook.numbers  (a single ZIP file, 101,035 bytes, 60 entries)
offset 0: 50 4B 03 04 …  "PK", a ZIP local file header

$ unzip -l sample-workbook.numbers   (abridged)
   7214  Index/Document.iwa                  the document: sheets, tables
   4362  Index/CalculationEngine.iwa
  45318  Index/DocumentStylesheet.iwa        cell, text and table styles
  17354  Index/Metadata.iwa                  which object lives in which file
     82  Index/AnnotationAuthorStorage.iwa   comment authors
    990  Index/Tables/Tile-1000042.iwa       a table's cells, row by row
    503  Index/Tables/DataList-1000021.iwa   a table's strings and formats
         … 47 more .iwa files …
    445  Metadata/Properties.plist           document IDs, format version
     36  Metadata/DocumentIdentifier
    341  Metadata/BuildVersionHistory.plist  which versions saved it
   9016  preview.jpg                         720 × 552 thumbnail
    879  preview-micro.jpg                   53 × 41
   1862  preview-web.jpg                     225 × 173

Index/Document.iwa, first bytes:
00 2a 1c 00         chunk header: type 0, length 0x001c2a = 7,210
b4 61               Snappy: 12,468 bytes when decompressed
f0 40               Snappy: a literal run of 65 bytes follows
3b                  Protocol Buffers: a 59-byte ArchiveInfo
  08 01             object identifier 1
  12 37             MessageInfo, 55 bytes:
    08 01           message type 1, the document (TN.DocumentArchive)
    12 03 01 00 05  version 1.0.5
    18 e6 0b        message length 1,510 bytes
  1. 150 4B 03 04

    The ZIP signature

    A single-file Numbers document is a ZIP archive, so it starts like an XLSX or any ZIP file. Rename a copy to .zip and you can open it. In our samples the entries are stored without ZIP compression, because the .iwa files are already compressed.

  2. 2Index/Document.iwa

    The document

    The root object: the list of sheets, and on each sheet the tables, charts, text boxes and images placed on it. Everything else is reached from here by object identifiers.

  3. 300 2a 1c 00

    An IWA chunk header

    Each .iwa file is a series of chunks: a 00 byte, then the chunk's length as a 3-byte little-endian number, here 7,210 bytes. This one chunk fills the rest of the file.

  4. 4b4 61 f0 40

    Snappy compression

    The chunk is compressed with Snappy, a fast compression method from Google. b4 61 is the decompressed size as a varint (12,468 bytes); f0 40 starts a run of 65 bytes copied as they are.

  5. 53b 08 01 12 37 …

    Protocol Buffers

    Decompressed, the data is a series of Protocol Buffers messages, Google's compact binary encoding. Each object starts with a small header, an ArchiveInfo, giving its identifier and the type and length of its messages. Type 1 is the document itself.

  6. 6Index/Tables/Tile-*.iwa

    The cells

    Table cells are stored in tiles, row by row, as compact binary records. Text and formats sit in separate lists (DataList-*.iwa) that cells refer to by number, much like shared strings in XLSX. Numbers are stored as 128-bit decimals, not binary floating point.

  7. 7Index/DocumentStylesheet.iwa

    Styles

    Paragraph, cell and table styles. At 45 KB it's the largest part of our samples: a new document carries the template's full set of styles, so even a nearly empty spreadsheet is around 90 KB.

  8. 8Metadata/BuildVersionHistory.plist

    Version history

    A list of the app versions that saved the document. Ours reads "Template: Blank (11.2)" followed by Numbers 12.0, 13.1 and 14.1 builds: the blank document numbers-parser starts from was last saved by Numbers 14.1. Properties.plist holds the file format version, 14.1.1.

  9. 9preview.jpg

    Preview images

    Thumbnails in three sizes. They're pictures, not data. In our samples they show the blank template, because numbers-parser doesn't draw new previews; a file saved by Numbers carries previews of its own content.

How Numbers thinks

Tables on a canvas, not one big grid

In Excel, a sheet is one huge grid that starts at A1. In Numbers, a sheet is a blank canvas, and tables are objects placed on it, next to charts, text boxes and images. Apple's guide puts it simply: "You can add as many tables as you want to a sheet." Each table has its own name, its own size and its own A1.

NumbersExcel
A sheet isA canvas with any number of tables and other objectsOne grid of cells, with charts and shapes floating above it
Cell referencesInclude the table: Table 2::B2, or Sheet 2::Table 1::C2 on another sheet (Apple's examples)Sheet and cell: Orders!G2
Headers and footersPart of each table: up to five header rows, five header columns and five footer rowsOrdinary rows, optionally formatted as a table
Interactive cellsCheckboxes, star ratings, sliders, steppers and pop-up menus are cell formatsForm controls and data validation lists
Empty spaceTables are only as big as they need to beThe grid is always 1,048,576 rows by 16,384 columns

This is why exporting to Excel asks a question: Numbers can make one Excel worksheet per table, optionally with a summary worksheet that links to all of them, or one worksheet per sheet.

Under the hood

How a Numbers file is stored

Since 2013, Numbers documents are made of IWA (iWork Archive) files, shared with Pages and Keynote. Apple doesn't document them. The SheetJS project, Sean Patrick O'Brien and the authors of keynote-parser and numbers-parser have worked out the structure:

  • Each .iwa file is Snappy-compressed in chunks: a 00 byte, a 3-byte length, then Snappy data.
  • Inside are Protocol Buffers messages. The message definitions are compiled into the apps; reverse engineers extract them from the app binaries.
  • Objects point to each other by number. Index/Metadata.iwa maps the document's components to the .iwa files that hold them, so a reader can find a table's cells without reading everything.
  • Tables are stored in tiles of rows. Text and formats are kept once per table and referred to by index.
  • Numbers are decimal. Current files store cell numbers as 128-bit decimal values, so 0.1 is stored exactly, unlike the binary floating point of Excel files.
Single file or package
Single file (default)Package
What it isOne ZIP fileA folder that macOS shows as one file
Good forEmail, uploads, cloud services used through a browserVery large documents, and documents edited on a Mac's own disk or in iCloud Drive
RiskCan get slow with very large documentsDamaged when emailed or uploaded through a browser, which sees a folder

You can switch between the two at any time in Numbers on a Mac: File, Advanced, Change File Type. Numbers may suggest a package for documents over 500 MB on disks that don't use APFS.

No Mac?

How to open a Numbers file on Windows, Android or Linux

  1. 1Use Numbers for iCloud. Go to iCloud.com in a browser on Windows or any computer, sign in with an Apple Account (creating one is free), open Numbers and upload the file. You can view and edit it there, then download a copy as Excel, PDF, CSV or Numbers.
  2. 2Ask the sender to export it. In Numbers: File, Export To, Excel (or CSV or PDF). This is the most reliable route, because the person exporting can check the result.
  3. 3Look at the preview, as a last resort. Rename a copy to .zip, open it, and open preview.jpg. It's only a small picture of the spreadsheet, not the data, and it may not show everything.

LibreOffice can import some Numbers files through its libetonyek library, but don't count on it for current files. When we opened our samples in LibreOffice 24.2, it recreated each table as a sheet with the right size and column widths, but every cell was empty.

How to

How to export or convert a Numbers file

Export formats in Numbers for Mac (File, Export To)
FormatWhat you get
ExcelAn .xlsx workbook, with one worksheet per table (optionally with a summary worksheet) or one per sheet.
CSVComma-separated text: one file per table, or all tables in one file, optionally with table names.
TSVThe same, separated by tabs.
PDFPages for printing or reading, with options for page layout, image quality and comments.
Numbers '09A file for Numbers 2.0 to 2.3. Large spreadsheets may fail to export in this format.
  • In Numbers for iCloud: download a copy as Numbers, PDF, Excel or CSV. With CSV, each sheet becomes a separate file.
  • Passwords carry over: exporting a password-protected spreadsheet to PDF, Excel or Numbers '09 keeps the password unless you change or remove it in the export dialog.
  • What can change in Excel: tables become ranges on worksheets, and Numbers features without an Excel equivalent can't come along as they are. Check formulas and totals after exporting.
  • From Excel to Numbers: open the .xlsx in Numbers with File, Open, then save it as a Numbers spreadsheet.
  • With code: numbers-parser, an open-source Python library, reads and writes .numbers files, and its cat-numbers command converts them to CSV. It can't write formulas.

Troubleshooting

Common Numbers file problems

  • Excel or Google Sheets can't open it. Neither reads .numbers files. Convert it through Numbers or iCloud.com first.
  • The attachment arrived as a folder, a ZIP or a broken file. The document was saved as a package. Ask the sender to choose File, Advanced, Change File Type, Single File, and send it again.
  • Windows shows an unknown file type. Windows has no program for .numbers. Use iCloud.com, or ask for an XLSX.
  • It asks for a password. Numbers documents can be encrypted, and without the password the contents can't be read. Ask the author for it, or for an unprotected export.
  • Totals look different after exporting. Some Numbers features have no exact equivalent in Excel or CSV. Compare a few totals with the original.
  • It won't open in an older Numbers. A file from a much newer version can use features an old app doesn't know. Update Numbers, or ask for a copy exported as XLSX.

Security

Is a Numbers file safe to open?

Numbers has no macro language inside documents, so a .numbers file can't carry VBA-style macros the way Excel files can. That removes the main risk of spreadsheet attachments. A few things are still worth knowing:

  • Preview images show content. The preview.jpg files inside an unencrypted document are pictures of the spreadsheet. Anyone who unzips the file can see them.
  • Comments and author names travel with the file, as do hidden rows, columns and filtered-out data.
  • Password hints are not secret. In our password-protected sample, the hint is stored as plain text in a .iwph entry, next to a .iwpv2 entry that lets an app check the password. Don't put the password in the hint, as we did for this test file.
  • Links in cells and text can point anywhere. Check where they go before clicking.
  • Parsing uploads on a server. A Numbers file is a ZIP of compressed binary data, so a server that reads uploaded files inherits ZIP risks such as archive bombs. Limit file size and decompressed size, and use a maintained library.

Free downloads

Sample Numbers files to download

Free sample .numbers files for testing uploads, converters and file-type detection. We made them with numbers-parser, an open-source Python library (MIT licence) that builds documents from a blank Numbers document, not with Numbers itself. Each one was read back with numbers-parser and every cell checked. numbers-parser can't write formulas, so totals are plain values.

sample-workbook.numbers · 98.7 KBDownload

Browsers can't show this kind of file in a page. Download it to open it in the app it belongs to.

What's inside sample-workbook.numbers

Browsers can't preview Numbers files, so download it and open it in Numbers on a Mac, iPhone or iPad, or upload it to Numbers at iCloud.com. It holds the same orders as our sample XLSX, so you can compare the two.

  1. Two tables on one sheet

    The Orders sheet holds two tables side by side: Orders on the left and By product to its right. In Excel this would be one grid; in Numbers they're separate objects you can drag around.

  2. Headers

    Orders has one header row and no header column; By product has a header row and a header column with the product names.

  3. Text, dates and euros

    Order IDs are text, so 000184 keeps its zeros. Dates use the format yyyy-MM-dd, and prices and line totals the euro currency format.

  4. Checkbox cells

    The Shipped column uses the checkbox cell format (numbers-parser calls it a tickbox): eight orders ticked, four not.

  5. Totals as values

    The bold totals row, under a 1 pt top border, holds 39 items and €255.07. They're stored values, not formulas.

  6. Caption

    A caption under the Orders table says the data is fictional.

  7. About sheet

    A title cell merged across two columns, notes on how the file was made, a date formatted as d MMMM yyyy, and a comment on cell B2 by "99helpers".

All sample Numbers files

  • Sample spreadsheet

    sample-workbook.numbers · 98.7 KB (101,035 bytes)

    Two sheets and three tables: twelve fictional orders with text IDs, dates, euro amounts and checkboxes, a summary table on the same canvas, and an About sheet with a merged cell and a comment. Saved as a single file.

    • Testing converters and file-type detection
    • Trying the Windows routes: iCloud.com and export
    Download

  • Minimal Numbers file

    sample-minimal.numbers · 90.8 KB (93,000 bytes)

    One sheet, one table: two items, their prices, a total and a note. Most of its 93 KB is the template's stylesheet, metadata and preview images.

    • Smoke tests for Numbers readers
    • Seeing what a near-empty document contains
    Download

  • Password-protected Numbers file (password: 99helpers)

    sample-password.numbers · 102.1 KB (104,510 bytes)

    The sample spreadsheet, encrypted with the password 99helpers. The .iwa entries are encrypted; .iwph holds the hint and .iwpv2 the data used to check the password.

    • Testing how uploads and converters handle encrypted documents
    • Checking password prompts and error messages
    Download

Ways to test with them

  • File-type detection: these files start with PK, so a check based on the first bytes calls them ZIP archives. Look for Index/Document.iwa inside to recognise a Numbers document.
  • Conversion: upload sample-workbook.numbers to Numbers at iCloud.com and download it as Excel. The Orders total should still be €255.07, and you should see how the two tables on one sheet were arranged.
  • Reading in code: cat-numbers -T sample-workbook.numbers (from numbers-parser) lists the three tables: Orders, By product and About this file. Without -T it prints every row as CSV; the Orders total row ends in 255.07.
  • Encrypted files: numbers-parser refuses sample-password.numbers without a password ("No password provided to decrypt document"); your import should report that clearly.

Free to use for testing, teaching and demos, commercially or not, with no attribution needed. A link back to this page is always appreciated.

Put it online

Have a Numbers file? Give it a link.

Drop a Numbers spreadsheet on 99helpers and it gets its own web address. Browsers can't display .numbers files, so anyone with the link downloads it and opens it in Numbers or at iCloud.com. Save it as a single file first, not a package.

Put a Numbers file online

Questions

Numbers files, frequently asked

What is a .numbers file?

A spreadsheet made with Apple Numbers, the free spreadsheet app on Mac, iPhone and iPad. It holds sheets with tables, formulas, charts and comments, stored as a ZIP of compressed binary archives.

How do I open a Numbers file on Windows?

Sign in at iCloud.com with an Apple Account, open Numbers and upload the file. You can view and edit it there, or download it as an Excel, PDF or CSV file. Alternatively, ask the sender to export it to Excel.

Can Excel open a Numbers file?

No. Excel doesn't read .numbers files. Convert the file to XLSX in Numbers (File, Export To, Excel) or at iCloud.com first.

Can Google Sheets open Numbers files?

No, .numbers isn't among the file types Google Sheets imports. Export the file to XLSX or CSV, then upload that.

How do I convert Numbers to Excel?

In Numbers on a Mac, choose File, Export To, Excel, and pick one worksheet per table or one per sheet. At iCloud.com, download a copy of the spreadsheet as Excel.

Is Apple Numbers free?

Yes. Numbers is free on Mac, iPhone and iPad, and in a browser at iCloud.com. Since early 2026, an optional Apple Creator Studio subscription adds extra templates, content and AI features.

Why is my Numbers file a folder?

It was saved as a package, a folder that macOS shows as one file. Open it in Numbers and choose File, Advanced, Change File Type, Single File before emailing or uploading it.

Can a Numbers file contain a virus?

Numbers documents can't contain macros, which is how most spreadsheet malware works. They can still contain links, so be careful with files you didn't expect, as with any attachment.

Related formats

Other file types explained

XLSX fileCSV fileODS fileXLSB fileZIP fileAll file types

Keep going

Related

Host a Numbers file

Put a Numbers spreadsheet online at its own address.

Share a Numbers file

Send a spreadsheet as a link instead of an attachment.

Host a report

Publish a report and the spreadsheet behind it.

Sources

Last reviewed 27 October 2026.