Free online OLM to XLSX converter

What the OLM format is

OLM is the mailbox archive format created by Microsoft Outlook for Mac. It can contain email messages, folders, attachments, contacts, calendar entries, and tasks exported from a Mac Outlook profile. OLM files are commonly encountered after using Outlook → Tools → Export for backup, migration, or account archiving.

OLM is a container for Outlook data rather than a spreadsheet. Excel cannot open it directly, and changing the filename extension does not convert its internal database structure.

What the XLSX format is

XLSX is the XML-based workbook format used by Microsoft Excel, LibreOffice Calc, Apple Numbers, and many browser-based spreadsheet applications. It stores worksheets containing rows, columns, formulas, formatting, filters, and multiple data types.

XLSX is appropriate when Outlook records must be sorted, searched, deduplicated, calculated, or imported into a database or reporting system. A converted workbook normally contains extracted fields such as sender, recipient, subject, date, folder, contact name, phone number, or appointment time; it does not preserve Outlook's mailbox behavior.

How to convert OLM to XLSX

Using the online converter

You can convert the file on the 101convert.com website for free without installing software:

1. Open the OLM-to-XLSX conversion page.
2. Select the .olm file from your computer.
3. Choose XLSX as the output format and start the conversion.
4. Download the generated workbook and open it in Excel, LibreOffice Calc, or another compatible spreadsheet program.

The converter must extract structured records from the archive before creating worksheets. Depending on the archive contents, separate sheets may be created for messages, contacts, calendar items, or tasks.

Using Outlook and a spreadsheet application

For contact data, a desktop workflow can avoid converting the entire mailbox archive:

1. Import the archive into Outlook for Mac through File → Import, if the installed Outlook version supports OLM import.
2. Export the required contacts or other supported records to a delimited file such as .csv using the relevant Outlook export command.
3. Open the CSV file in Excel or LibreOffice Calc.
4. Check the delimiter, character encoding, date columns, and leading zeros during import.
5. Save the result through File → Save As and select Excel Workbook (*.xlsx).

This method is useful when only contacts are needed, but Outlook's available export commands vary between classic Outlook for Mac and newer Outlook versions. If the OLM contains email or calendar data that Outlook cannot export directly, use a converter that explicitly supports those record types or extract the data with a specialized desktop utility before saving it as XLSX.

Quality and compatibility limits

An OLM-to-XLSX conversion is a data extraction, not a complete mailbox migration. Attachments may be represented by filenames or omitted, HTML email formatting may be reduced to text, embedded images may not become worksheet objects, and Outlook folders, flags, categories, threading, permissions, and message metadata may not map cleanly to spreadsheet columns.

Large archives can produce large workbooks or multiple worksheets. Verify row counts against the original archive, inspect dates and time zones, and check contact fields containing commas, line breaks, non-Latin characters, or leading zeros. Never store email bodies or personal data in a third-party system unless its handling meets your privacy and retention requirements.