Written by Jennifer Walsh. Reviewed for technical accuracy by Shubham Dixit, Independent Expert in Email Forensics and Data File Conversion.
Shubham is an independent external reviewer and not an employee of PCDOTS.
Quick answer. An OLM file is Outlook for Mac’s own format, and Gmail cannot read it. If you still have Outlook for Mac, add your Gmail account there over IMAP and move the mail up. If you only have the OLM file, a converter reads it and uploads it to Gmail directly. Either way the mail travels by IMAP, and calendars and contacts move separately.
On this page
Why OLM is the awkward part?
The reason this is fiddlier than a normal mailbox move is the file itself. OLM is Outlook for Mac’s own archive format, and almost nothing else can read it. Gmail certainly cannot, and unlike a PST there is no free tool like Thunderbird that opens an OLM for you. So the OLM has to be opened by something that understands it before its mail can go anywhere.
That leaves two honest paths. If you still have Outlook for Mac, it is the key, you open the OLM there and push the mail to Gmail over IMAP for free. If you do not, or you are holding a bare OLM file on a Windows PC, a converter that reads OLM directly is the practical answer. Everything below follows from which of those you are.
Something has to open the OLM first. Then the mail rides IMAP to Gmail.
“OLM is the difficult child of email formats. A PST you can crack open with free tools, but an OLM is closed enough that in practice only Outlook for Mac reads it cleanly, which is why so many people get stuck. Once it is open the rest is ordinary, Gmail speaks IMAP, so the mail uploads like any other account. The part I always flag is that IMAP only moves mail, the calendar and contacts inside an OLM are a separate export, and people forget them until they are missing.” Shubham Dixit, Email Migration reviewer (draft, pending approval)
The free way, through Outlook for Mac
If Outlook for Mac is still on the machine, you can do this without spending anything, because it can both open the OLM and talk to Gmail over IMAP.
Open the OLM. If the mail is already in Outlook for Mac you can skip this. For a standalone file, go to File, Import, choose Outlook for Mac Data File, and bring the OLM in.
Add your Gmail account. In Outlook for Mac, add your Gmail account, which connects over IMAP. Your Gmail folders now appear alongside the imported OLM mail.
Move the mail up. Select the messages from the OLM and drag or copy them into a Gmail folder or label. Because it is IMAP, everything you drop there uploads to Gmail in the background, and within a while your OLM mail is in your Gmail account.
Where the mail, calendar and contacts land?
Worth setting expectations here, because an OLM holds more than mail. IMAP only carries the mail, so that is what lands in Gmail. The OLM’s calendar and contacts do not ride IMAP and will not appear in Gmail on their own.
Those move as a separate, quick step. From Outlook for Mac export the calendar as an ICS file and import it into Google Calendar, and export contacts as a vCard and import them into Google Contacts. Plan for that and nothing goes missing.
Mail rides IMAP into Gmail. Calendar and contacts take their own short route.
No Outlook for Mac, a converter
Here is where a paid tool genuinely earns its place, more than it does for most formats. Because OLM has no free reader, if you do not have Outlook for Mac, or you are working from a Windows PC with just the OLM file, there is no free path, and a converter is the sensible answer. The PCDOTS OLM Converter reads the OLM directly on Windows and uploads the mail straight into your Gmail account over IMAP, in bulk, without Outlook for Mac anywhere in the picture. It also works for a Google Workspace account. The mail is what travels this way, so handle calendars and contacts as above. A free version uploads the first ten items per folder so you can confirm it works on your data first.
The tool route, when Outlook for Mac is not an option.
Here are the steps with the screens.
Step 1. Install and run the converter on Windows, then open the menu.
Step 2. Choose Email Data Files, Outlook for Mac OLM, and add your files.
Step 3. Open the Export menu and choose Gmail.
Step 4. Enter your Gmail login and start the upload.
If your destination is different, see our guides to import OLM to Windows Outlook and import OLM to Office 365, and for a similar upload from a PST, import PST to a Gmail account.
The methods compared
Match the route to whether Outlook for Mac is within reach.
| Method | Best for | Good to know |
|---|---|---|
| Outlook for Mac over IMAP | You still have Outlook for Mac, free | Mail only, drag into Gmail folders |
| OLM Converter tool | No Outlook for Mac, or bulk | Reads OLM on Windows, uploads mail |
| Calendar and contacts | The non-mail items | ICS and vCard, imported separately |
Frequently asked questions
Can Gmail import an OLM file directly?
No. OLM is Outlook for Mac’s closed format and Gmail cannot read it. You open the OLM with Outlook for Mac or a converter first, then the mail uploads to Gmail over IMAP.
How do I import OLM to Gmail for free?
If you have Outlook for Mac, import the OLM into it, add your Gmail account over IMAP, then drag the messages into a Gmail folder. They upload to Gmail in the background.
Is there a free tool that reads OLM without Outlook for Mac?
Not a reliable one. Unlike PST, OLM is closed, so free readers do not handle it well. Without Outlook for Mac, a dedicated converter is the practical route.
Will my calendar and contacts go to Gmail too?
Not over IMAP, which carries mail only. Export the OLM’s calendar as ICS into Google Calendar and contacts as vCard into Google Contacts as a separate step.
Can I upload many OLM files at once?
Yes. A converter can process a batch of OLM files and upload them to Gmail in one pass, which is easier than dragging folders manually for large mailboxes.
Does this work with Google Workspace?
Yes. The same IMAP upload works for a Google Workspace account, not just a personal Gmail one.
It comes down to what you still have
Everything here turns on one detail. If Outlook for Mac is still on your machine, importing an OLM to Gmail costs nothing, you open the file there and drag the mail into your Gmail folders over IMAP, then bring the calendar and contacts across as ICS and vCard. If it is gone and you are left with a lone OLM file, its closed format is what makes a converter genuinely worth it, so it can read the OLM and upload straight to Gmail. So before you look for a method, which is it for you, do you still have Outlook for Mac in reach, or just the file?
