How do I move my Outlook for Mac mail to Outlook on Windows?

Export it from Outlook for Mac as an .olm (File, Export), convert the .olm to a PST here, and open the PST in Outlook for Windows with File, Open & Export, Open Outlook Data File. To have the mail in the mailbox itself rather than in a separate file, drag the folders from the PST into it, or use Import/Export, Import from another program or file, Outlook Data File.

Are contacts and calendar items in the OLM converted?

No, only the mail. The page says when the archive also holds contacts, calendar entries, notes or tasks, which stay in the .olm.

Does the PST keep the original email headers?

An .olm keeps no original internet headers - only the fields Outlook for Mac shows, which are what the PST is made from. Everything you see in Outlook (sender, recipients, dates, subject, body, attachments) is there; the Received lines of the mail servers are not, as the archive never had them.

Stays on your computer Needs a desktop or laptop browserHow this works

Convert OLM to PST

Turn an Outlook for Mac archive (.olm) into an Outlook for Windows data file (.pst), with its folders, attachments, dates and read flags. Free, no Outlook needed, and nothing is uploaded.

Drag & drop an .olm file here, or browse

.olm from Outlook for Mac · any size · nothing is uploaded

Or : its subfolders become folders in the PST.

About converting OLM to PST

An .olm file is what Outlook for Mac makes with File, Export: an archive of the mailbox, each email stored as its own small XML file with its attachments beside it. Outlook for Windows has never opened .olm files, so moving from a Mac to a Windows PC - or handing a Mac user's mail to someone on Windows - usually means a paid converter.

This page reads the archive in your browser and writes an Outlook for Windows .pst from it, with the archive's folders: Inbox, Sent Items, your own folders and the folders inside them, under each account when the archive holds several. Every email keeps its sender, recipients (To, Cc and Bcc), the time it was sent and received, subject, Message-ID, plain and HTML body, attachments, pictures in the body, and read or unread. The archive is read entry by entry and the PST written as it goes, so a large archive does not have to fit in memory. It is free to use, with no account and no upload limit, and it runs entirely in your browser: nothing is uploaded, and while the page stays open, a feature you have already used keeps working offline.

What you can do

Convert an Outlook for Mac .olm archive to a .pst for Outlook on Windows, folders kept
Keep attachments, pictures in the body, HTML formatting, read and unread, and the Message-ID
Convert archives with several accounts: each account becomes a folder
Add saved .eml or .msg files, or an mbox mailbox, to the same PST

How to convert an OLM file to PST

In Outlook for Mac, choose File, Export, tick Mail, and save the .olm.
Drop the .olm onto this page, on the Mac or on the PC. The folders and the number of emails appear.
Press Make the PST file. In Chrome and Edge, choose where to save it first; it is written there as it goes.
In Outlook for Windows, choose File, Open & Export, Open Outlook Data File, and pick the PST.

Questions

How do I move my Outlook for Mac mail to Outlook on Windows?: Export it from Outlook for Mac as an .olm (File, Export), convert the .olm to a PST here, and open the PST in Outlook for Windows with File, Open & Export, Open Outlook Data File. To have the mail in the mailbox itself rather than in a separate file, drag the folders from the PST into it, or use Import/Export, Import from another program or file, Outlook Data File.
Are contacts and calendar items in the OLM converted?: No, only the mail. The page says when the archive also holds contacts, calendar entries, notes or tasks, which stay in the .olm.
Does the PST keep the original email headers?: An .olm keeps no original internet headers - only the fields Outlook for Mac shows, which are what the PST is made from. Everything you see in Outlook (sender, recipients, dates, subject, body, attachments) is there; the Received lines of the mail servers are not, as the archive never had them.

To read an .olm without converting it, or save emails from it as .eml and .mbox, open it in the OLM Viewer. The PST this makes opens in the PST Viewer too.