Lotus 1-2-3

Lotus 1-2-3 is a legendary spreadsheet application that was frequently used as a data store. It represents data as cells in worksheets.

What You Can Upload

• .wks files (Lotus 1-2-3 Release 1/1A)
• .wk1 files (Lotus 1-2-3 Release 2)
• .wk3 files (Lotus 1-2-3 Release 3)
• .wk4 files (Lotus 1-2-3 Release 4-5)
• Symphony .wrk/.wr1 files
• ZIP archive with multiple files

What You Get Out

DataMeans extracts your data into multiple modern formats:

How to Export / Obtain Files

1. Locate your Lotus 1-2-3 files
2. Upload directly or in a ZIP archive
3. No special export needed

Supported Features

• Cell-by-cell data extraction
• Named range identification
• Multiple worksheet support
• Numeric and text cell types
• Date value conversion
• Simple table detection

Known Limitations

• Formulas exported as calculated values
• Charts and macros not extracted
• Structure inferred from cell layout (not normalized)
• Very complex layouts may need manual review

Last updated: January 2026

Overview

Lotus 1-2-3 is a discontinued spreadsheet application that was the first "killer app" for the IBM PC, revolutionizing personal computing by making spreadsheets accessible to business users. Originally developed by Lotus Development Corporation, it combined spreadsheet calculations, charting, and basic database functionality into an integrated package. Lotus Development was acquired by IBM in 1995, and 1-2-3 was officially discontinued in 2013.

History and Background

• 1982: Lotus Development Corporation founded by Mitch Kapor and Jonathan Sachs. Kapor had previously created VisiPlot and VisiTrend for the distributor of VisiCalc; Sachs had worked at Data General and Concentric Data Systems.
• January 26, 1983: Lotus 1-2-3 Release 1 released, priced at $495. It sold 175,000 copies in its first year and quickly displaced VisiCalc as the dominant spreadsheet application.
• 1985: Release 2 introduced an advanced macro command language, add-in support, and expanded memory support.
• 1989: Release 3 added 3D worksheets, support for multiple open files, and use of extended memory.
• 1990: Lotus won its three-year copyright suit against Paperback Software International and Mosaic Software, publishers of the 1-2-3 clones VP-Planner and The Twin.
• 1991: 1-2-3/W Release 1, the first version for Microsoft Windows, shipped.
• 1993: Release 4 for Windows added groupware capabilities, improved integration with Lotus Notes, and in-cell editing.
• 1994: Release 5 for Windows added chart maps and improved database access.
• 1995: IBM acquired Lotus for $3.5 billion, primarily for Notes but including 1-2-3.
• 1996: Lotus v. Borland, a six-year suit over Quattro Pro's copying of the 1-2-3 menu command hierarchy, ended when a 4-4 Supreme Court affirmed that the menu hierarchy was an uncopyrightable method of operation.
• 2013: Lotus 1-2-3 discontinued after 30 years; support ended on September 30, 2014.

File Format Specifications

Lotus 1-2-3 uses a proprietary binary file format organized as an unbroken sequence of variable-length records. Each record consists of a 4-byte header followed by the record body. The header contains the record type code (2 bytes) and the record body length (2 bytes), both stored in little-endian byte order.

File Extensions:

• .WKS - Releases 1 and 1A
• .WK1 - Release 2.x
• .WK3 - Release 3.x
• .WK4 - Releases 4 and 5 for Windows
• .123 - 1-2-3 97 Edition and later

Record Structure:

• Header: 4 bytes (2-byte record type code + 2-byte body length)
• Body: Variable length based on record type
• Records are stored sequentially without index
• File starts with BOF (Beginning of File) record and ends with EOF (End of File) record
• BOF format revision numbers identify the generation: 0x0404 (.WKS), 0x0406 (.WK1), 0x1000 (.WK3), and 0x1002 (.WK4); the BOF body grows from 2 bytes in .WKS/.WK1 to 26 bytes in .WK3/.WK4
• Cell records share a 5-byte body prefix: a 1-byte format byte, a 2-byte column number, and a 2-byte row number, followed by the cell value
• The format byte stores cell protection in bit 7, the display format type (Fixed, Scientific, Currency, Percent, Comma, or Special) in bits 4-6, and the decimal-place count in bits 0-3
• Special display formats carry date and time picture codes as well as Text and Hidden cell settings in the low 4 bits
• LABEL record bodies begin with an alignment prefix character: ' (left), " (right), or ^ (centered)

Key Record Types:

• 0x00: BOF (beginning of file; 2-byte format revision number)
• 0x01: EOF (end of file marker)
• 0x06: RANGE (worksheet range record; 8-byte body)
• 0x0B: NAME (named range)
• 0x0C: BLANK (empty formatted cell)
• 0x0D: INTEGER (integer cell value)
• 0x0E: NUMBER (floating-point cell value)
• 0x0F: LABEL (text label cell)
• 0x10: FORMULA (calculated cell)

Data Types and Structures

Spreadsheet Structure:

• Grid-based layout with 256 columns (A-IV); 2,048 rows in Release 1, expanded to 8,192 rows in Release 2
• Cells identified by coordinates (e.g., A1, B2); numbering in the file starts at column 0, row 0
• Built-in functions begin with the @ symbol (@SUM, @AVG, etc.)
• Supports absolute ($A$1) and relative (A1) references
• Macros recorded as keystroke sequences; Release 2 added a macro command language comparable in complexity to a BASIC interpreter

Version Differences

Compatibility Notes:

• Most major releases introduced a new file format; older releases cannot open the newer formats
• Lotus published the Release 1/1A worksheet file format documentation in 1984, enabling third-party tools to read and write worksheet files
• Lotus Symphony used a closely related record format; Symphony could read 1-2-3 records, but 1-2-3 could not read Symphony-specific records
• Older versions of Microsoft Excel could open Lotus worksheet files; Excel 2010 removed support for the formats
• 1-2-3's serial date system incorrectly treats 1900 as a leap year; Microsoft Multiplan and Excel deliberately adopted the same assumption so their serial dates would match 1-2-3 worksheets, and Excel retains the behavior
• Apache OpenOffice and LibreOffice retain import support for .WKS, .WK1, and .123 files
• The UK National Archives' PRONOM registry catalogues the worksheet generations under separate identifiers (x-fmt/117 for .WKS, x-fmt/114 for .WK1, x-fmt/115 for .WK3, x-fmt/116 for .WK4), distinguished by their BOF signatures

Technical References

• Wikipedia: Lotus 1-2-3
• Lotus Worksheet File Format documentation (1984, archived)
• ArchiveTeam File Format Wiki: Lotus 1-2-3
• Wikipedia: Lotus Development
• FileFormat.com: Lotus .123 File Format

To learn how to use this format with DataMeans, see the User Guide.