Lotus 1-2-3 files

Current versions of Excel don't open Lotus 1-2-3 files. Drop a .wk1, .wk3, .wk4 or .123 file into the converter above and you get an Excel workbook back, with every sheet and every cell value, read inside this browser tab. Formulas arrive as the results Lotus last calculated.

Updated 19 October 2026 · How we test this format

Excel or CSV?

The converter on this page reads every version of Lotus, whatever its label says. Choose Excel or CSV under To, then add your files. Excel suits looking through the data, sorting and sharing it; CSV suits loading it into a database, a script or another program.

A CSV writes decimals with a point, whichever delimiter you pick. A spreadsheet set to a language that writes decimals with a comma can read a value like 683.38 from our soil survey sample as text: Numbers 14.5 with Turkish region settings did. If you'll work with the numbers in a spreadsheet, choose Excel.

What a Lotus 1-2-3 file is

Lotus 1-2-3 came out in January 1983 and soon became one of the main reasons people bought an IBM PC. For the rest of the 1980s it was the standard spreadsheet in offices, and its files went everywhere: budgets, ledgers, price lists, tax workings, survey results and lab measurements. IBM bought Lotus in 1995 and kept 1-2-3 going as part of the SmartSuite package, but it is no longer sold, and Excel took over its users long ago.

The files didn't go away. They sit in accounting and legal archives, on backup discs from retired office PCs, in government and university data sets published in the 1980s and 1990s, and in the folders of anyone who kept their own records for decades. When one of them is needed again, for an audit, a claim or a piece of research, the program that made it is usually long gone.

Inside, a Lotus file is a run of short binary records, each with a type and a length: one record per cell, plus records for the sheet's settings. Text cells begin with a label prefix that sets their alignment: an apostrophe for left, a quote for right, a caret for centred. We remove these, along with the backslash and bar prefixes, so a cell reads "DATE" rather than "^DATE".

Versions and file extensions

• .wks Release 1 and 1A, for DOS
• .wk1 Release 2, for DOS
• .wk3 Release 3, with several sheets in one file
• .wk4 Release 4 and 5 for Windows
• .123 1-2-3 97 and Millennium Edition

The extension tells you which layout is inside. Release 1A and Release 2 files hold one sheet and keep a number format with each cell, so dates arrive as dates. From Release 3 on, a file can hold many sheets, tabbed A, B, C, and the formats live in separate tables that we don't read yet: dates arrive as serial numbers you can format in Excel. The notes below explain why that is quick to fix.

Next to a .wk1 or .wk3 you may find a .fmt or .fm3 file. Those hold the print formatting added by Lotus's WYSIWYG add-ins, such as fonts and lines, and no cell values, so convert the worksheet itself. We read the file's contents rather than trusting its name, which means a worksheet with the wrong extension still converts as long as the extension is one listed above.

The rows are measured, not promised: they come from our test files, and our tests fail if a number drifts from what the converter actually does. Each conversion also gets its own What changed list under the file, with counts for that file.

Why Excel won't open them any more

Older versions of Excel opened Lotus files directly. Microsoft's list of Excel file formats now puts every Lotus 1-2-3 format among the formats no longer supported, from Excel 2007 onwards, and the page doesn't mention .123. The usual advice is to install LibreOffice or Gnumeric, both free desktop spreadsheets that still read Lotus files, or to send the file to an online converter. This page does the reading in your browser instead, so there's nothing to install and the file never leaves your device.

What we read, and what stays behind

• Formulas. Lotus stores each formula together with the result it last calculated. We write that result into the cell. Lotus formulas use their own syntax, such as @SUM(A1..A10), and we don't translate them, so the workbook holds values that won't recalculate.
• Dates in newer files. Lotus and Excel count days the same way, from the start of 1900, so a serial number like 32368 is the same day in both. Select the column in Excel, choose a date format, and the dates reappear exactly as they were. LibreOffice Calc works the same way. Numbers keeps dates as a separate type, and in Numbers 14.5 a date format leaves these numbers as numbers.
• Text. Release 3 and later files use Lotus's own character set, which we decode. For older files we read accented letters as Western European text; if they look wrong, choose another Text encoding in the converter and add the file again.
• Sheets. Each Lotus sheet becomes an Excel sheet. Names stored in the file come across; a sheet without one is called Sheet1, Sheet2 and so on, as LibreOffice names them.
• What stays in the original. Graphs, macros, range names, fonts, shading and column widths. The notes under every converted file say so.

How we test

The table above comes from running the real converter on 10 licensed Lotus test files, taken from the test suites of the open-source Apache Tika and LibreOffice projects, plus files we generated. Between them they cover the .wks, .wk1, .wk3, .wk4 and .123 formats. We compare every cell with what LibreOffice and Gnumeric, two independent spreadsheet apps, read from the same file: 3,474 of 3,474 cells match.

The same check runs on the other formats this page accepts. In 19 test files from Excel 2.x to 95, Works, SYLK and DIF, 4,611 of 4,613 cells match. These are small test files rather than real archives, so treat the numbers as a check on the reading, not a guarantee for every file. Our tests run them again on every change to the code.

Quattro Pro files get the same check: in 6 test files from Apache Tika, one of each format from .wq1 to .qpw, 1,318 of 1,326 cells match. Only one of them is a .qpw notebook, and it holds a single cell, which is why we ask you to look over a converted .qpw before relying on it.

When a Lotus file won't convert

The file's row tells you when something stops a conversion. Here's what each message means and what to do.

• "This format isn't on our list yet" The extension isn't one this page takes. A .fmt or .fm3 file holds formatting only; pick the worksheet next to it.
• "This file isn't one we can convert with this tool." The contents aren't a spreadsheet format we read, even though the name says so. It may be a word processor document, or a text or web page export given a spreadsheet extension.
• "This file is password protected. Remove the password in the original app, then try again." The file was saved with a Lotus password, and its contents are scrambled. Open it in 1-2-3 with the password and save it without one.
• "This file looks damaged, or it isn't the format its name suggests." The file is cut short or isn't a Lotus file at all. Copies taken from old floppy discs sometimes end early; try another copy if you have one. When only a few records are damaged, the rest converts and What changed counts the records skipped.
• "This file is on the large side" Files over 20 MB ask before they start, and you can always continue. Lotus files are seldom that big.
• "This file is too large to convert on this device. A smaller file or more memory may help." Or, for Excel, a message that the file has more cells than one workbook can hold here. A workbook holds up to 8,000,000 filled cells; past that, convert to CSV. CSV goes further, but stops too when the sheets together span tens of millions of cells, counting the empty ones. Lotus files rarely reach either limit.
• "Something unexpected stopped this conversion. If trying again doesn't help, reload the page." Reload the page and convert the file once more. If the same file keeps failing, it probably uses something our reader doesn't handle yet.

What this page doesn't do

It only reads Lotus files; there's no conversion from Excel back to WK1 or WK4, because no current program needs them. It doesn't rebuild formulas, graphs or macros either. Those are written in Lotus's own languages, and translating them reliably is a separate project we haven't taken on. If you need a formula, the value next to it and the Lotus syntax above are usually enough to write the Excel version by hand.

Try it with a sample file

Download sample-soil-survey.wk1 (24 KB), a Release 2 worksheet of soil measurements from Apache Tika's test set, and drop it above. You'll get one sheet of 1,250 cells, with its dates as real dates; What changed reports the 160 formula cells that arrived as values and six cells holding values a spreadsheet can't store. For a newer file, try sample-lotus-cells.123 (4 KB), a small 1-2-3 97 workbook from LibreOffice's tests. Their sources and licenses are in the sample notes.

Tested on 14 October 2026: the soil survey, converted to Excel, opened in Numbers 14.5, with its dates as dates, and in LibreOffice Calc 26.8.1.1, both on macOS 26.2. LibreOffice shows the error cells as #NUM!; Numbers shows them empty, although the error is still in the file.