Email Migration Guide
By To import PST to Gmail, Google's own route is Google Workspace Migration for Microsoft Outlook (GWMMO): install it, sign in to the Google account, choose From PST file, pick the file and let it upload mail, contacts and calendar as Gmail labels. It needs Outlook on the PC and works for Workspace accounts. Without Outlook, or for a personal Gmail account, use a tool that reads the PST and uploads straight to Gmail over IMAP, such as Univik PST Converter. For a whole company, admins use GWMME from the Admin console. Gmail throttles IMAP uploads at about 500 MB a day per account, so any IMAP route is a slow one for large files.
A PST file is Outlook's world. Gmail has never opened one and never will, so the question is not how to open it but how to import Outlook emails to Gmail as labelled messages. Google offers a real tool for that, though it leans on Outlook being installed and on the account being Workspace rather than a free Gmail. Outlook itself can copy folders into a Gmail account over IMAP at a pace Google throttles hard. Admins moving a company have a third route from the Admin console. And when the PC has no Outlook, a converter that speaks IMAP is the way in. This guide walks all four, with Google's limits at the points where they bite.
- Before you import PST to Gmail
- Import with GWMMO in 5 steps
- Step 1: Check the account, storage and Outlook
- Step 2: Install GWMMO and sign in
- Step 3: Choose From PST file and pick the file
- Step 4: Pick what to migrate and the date range
- Step 5: Run it and check the labels in Gmail
- Outlook over IMAP
- GWMME for many users
- Direct upload without Outlook
- Method comparison
- After the import
- Fix common problems
- PST to Gmail questions
Before You Import PST to Gmail
Which Gmail, and is Outlook on the PC? Those two facts pick the route.
- Free space in the Google accountA free Gmail account has 15 GB shared with Drive and Photos. Business Starter has 30 GB per user pooled; higher editions have 2 TB or more. A 50 GB PST does not fit in a free account, whatever the tool.
- The PST opens in Outlook and has no passwordEvery Google route reads the file through Outlook and needs an Outlook version at least as new as the PST. Remove any PST password first.
- Which PST items you needMail is the point. Contacts and calendar come across with GWMMO and GWMME; IMAP routes carry mail only. Messages over 25 MB are skipped by Google's tools.
- Time, if IMAP is involvedGmail allows roughly 500 MB of IMAP upload per account per day and locks the account for a while when it is exceeded. A 10 GB PST over IMAP is a three week job.
- GWMMO
- Google Workspace Migration for Microsoft Outlook. Google's desktop tool for one to twenty users that migrates an Outlook profile or PST files into a Workspace account.
- GWMME
- Google Workspace Migration for Microsoft Exchange. Google's server tool for admins that migrates many users from Exchange, IMAP or PST files. It can also target Vault.
- GWSMO
- Google Workspace Sync for Microsoft Outlook. Lets Outlook work against a Workspace mailbox and offers an Import data option that uses GWMMO underneath.
- IMAP upload limit
- Gmail's bandwidth rule: about 500 MB uploaded per day per account over IMAP, 2,500 MB downloaded. Exceed it and Gmail locks the connection for up to 24 hours.
- Label
- Gmail's equivalent of a folder. A message can carry several. PST folders become nested labels, and a message that sat in two folders becomes one message with two labels.
Import PST to Gmail with GWMMO in 5 Steps
This is Google's supported route for a person moving their own mail. It uses Outlook on the PC to read the PST and uploads through Google's APIs, so it is not bound by the IMAP daily limit.
Check the Gmail account, the storage and Outlook
GWMMO signs in to a Google Workspace account; a consumer Gmail address is not the target it was built for, so for a personal account skip to the direct upload. Confirm the account has room for the PST and that classic Outlook is installed on the PC. The tool supports Outlook 2010 through 2024 and Microsoft 365 Apps. Copy the PST to a local drive rather than a network share.
Install GWMMO and sign in to the Gmail account
Download Google Workspace Migration for Microsoft Outlook from Google's Workspace admin help, run the installer and start it. Sign in with the Workspace account that should receive the mail. The Workspace admin may need to allow the tool in the Admin console first if third-party app access is restricted.
Choose From PST file in GWMMO and pick the file
The first page asks what to migrate from: the Outlook profile on the PC, or PST files. Choose From PST file(s) and select the file, or several, to import. Choose Migrate all data on the first run. Migrate only new data is for a second pass after more mail has landed in the PST.
Step 3From PST file(s). The tool reads the file through Outlook and uploads through Google's API.
Pick what to migrate from the PST and the date range
Tick Email messages, and Calendar and Contacts if the PST holds them. Set a start date if the account only needs recent years. Leave junk and deleted items unticked unless they are wanted. Messages over 25 MB are skipped and listed in the log; that is Google's rule, not the tool's.
Step 4Mail, calendar and contacts ticked, a start date set. Items over 25 MB are skipped.
Run the GWMMO import and check the labels in Gmail
Click Migrate. Progress shows per item type; a 10 GB PST takes a few hours on a normal connection. When the import finishes, open Gmail. The PST's folders appear as nested labels under a parent label named after the file or the profile. A message that lived in two Outlook folders is now one message with two labels, which is Gmail de-duplicating on purpose. Spot check a message with an attachment and one from the oldest year.
You should seethe folder tree as labels in the left pane and counts that match the PST folder counts once duplicates are taken into account. The log lists anything skipped.
| From | Subject | Date | |
|---|---|---|---|
| ☆ | Sarah Chen | Re: Supplier contract renewal · contract-v3.pdf | 12 Mar 2016 |
| ☆ | Mike Turner | Q2 partnership update | 11 Mar 2016 |
| ☆ | Legal, Vendor | Updated agreement for review · agreement.docx | 10 Mar 2016 |
| ☆ | David Kim | Meeting next week | 9 Mar 2016 |
PST folders arrive as nested labels under one parent label. Original dates and attachments are kept.
Step 5PST folders as nested labels. Dates and attachments intact.
Import PST File to Gmail with Outlook over IMAP
The manual route needs nothing but classic Outlook. Add the Gmail account to Outlook as an IMAP account, with IMAP enabled in Gmail settings first and a Google sign-in or an app password. Attach the PST through File, Open & Export, Open Outlook Data File. Then copy folders from the PST into the Gmail account in the folder pane, one folder at a time. Outlook uploads them as it goes. Every folder becomes a label.
Two things make this slow and one makes it fragile. Gmail's IMAP upload limit is about 500 MB a day per account, so a 5 GB PST is ten days of copying. Going over the limit locks the account for hours. Outlook stalls on very large copies, so work in batches of a few hundred messages. And Gmail's All Mail folder shows Outlook every message a second time, which doubles the size of the local cache and confuses search. It works for a small PST and a patient person. It is the wrong tool for anything measured in gigabytes.
Import PST to Google Workspace for Many Users with GWMME
An administrator moving a company runs Google Workspace Migration for Microsoft Exchange on a Windows server. Among its sources it accepts PST files: one file, or a folder of them, mapped to Workspace users by a CSV. It needs Outlook on the server at least as new as the PST files, and the files must not be password protected. It can write into Vault for retained data. Google's newer data migration service in the Admin console migrates from Exchange, IMAP and Gmail sources but does not take PST files. Google Workspace Migrate does not either. GWMME is the route Google supports to import PST to Gmail accounts at scale. Plan the CSV mapping, run a pilot user, then batches.
If the move is the other way, out of Google, the PST is the destination rather than the source. The Google Vault to Office 365 migration guide covers the export side and how to import PST to Office 365 covers the Microsoft side.
Import PST File to Gmail Without Outlook: Direct Upload
The gap in Google's toolset is the PC with no Outlook, and the personal Gmail account. To upload PST to Gmail there, the tool has to read the file itself. Univik PST Converter reads the PST file itself, including ANSI files and orphan files no Outlook profile knows about. It offers Gmail as an output alongside Office 365 and any IMAP server.
- Add the PST and preview itAdd File loads the PST without Outlook. Browse the folders, check counts and untick anything not wanted, such as Deleted Items or a year that is already in Gmail.
- Choose Gmail as the outputSign in to the Gmail or Workspace account. Keep the folder tree as nested labels, or put everything under one label named for the archive.
- Let it pace the uploadThe upload goes over IMAP, so Gmail's daily limit applies. The tool pauses at the limit and resumes, and items over 25 MB are skipped and logged rather than failing the run.
- Check the log against GmailPer-message logging shows what landed under which label. For a big PST, filter by year and run several sessions rather than one month-long job.
Direct uploadGmail as the output, folders as labels, paced within the daily IMAP limit.
The honest limit is Gmail's, not the tool's. Direct upload is the right answer for a personal account or a PC without Outlook. For a large Workspace mailbox with Outlook available, GWMMO's API path is faster.
Univik PST Converter reads PST files without Outlook, uploads to Gmail, Google Workspace, Office 365 or any IMAP server with the folder tree kept as labels, paces itself within Gmail's daily limit and logs every message. Also writes EML, MBOX, PDF and more.
Windows 11 / 10 · Outlook not required · the free trial uploads the first 25 items per folder so you can see the labels in Gmail before you buy
PST to Gmail Method Comparison
| Method | Cost | Needs Outlook | Personal Gmail | Speed | Contacts and calendar | Best for |
|---|---|---|---|---|---|---|
| GWMMO | Free | Yes | Workspace only | API, hours | Yes | One Workspace user with Outlook |
| Outlook over IMAP | Free | Yes | Yes | 500 MB a day | Mail only | A small PST and patience |
| GWMME | Free | Yes, on the server | Workspace only | API, batched | Yes | Admins moving many users |
| Univik PST Converter direct upload | Trial, then licence | No | Yes | IMAP, paced | Mail only to Gmail | No Outlook, personal Gmail, orphan PST |
After the PST to Gmail Import
- The PST folders appear as labels in Gmail and the message counts match the PST folder counts once multi-folder duplicates are allowed for
- A message with an attachment from the oldest year opens in Gmail with the attachment and the original date
- The tool's log or GWMMO's report shows only the over-25 MB items as skipped, and you have a plan for those
Keep the PST for a few weeks after the import in case something was filtered out. Messages over 25 MB can be saved as EML or PDF from the PST and stored in Drive next to a note in Gmail. If the goal was to keep an old Outlook archive readable rather than to live in Gmail, an alternative is a free online PST viewer or a conversion to PDF. And if Gmail is one stop before Microsoft 365, the email archive migration guide lays out the whole route.
Fix Common PST to Gmail Problems
Three problems account for most stalled PST to Gmail imports. The red box is the symptom and the green box is the fix.
Do this: You hit the IMAP bandwidth limit of about 500 MB a day. Wait for the lock to clear, then use a tool that paces itself. Or switch to GWMMO if the account is Workspace and Outlook is available.
Do this: The target is a personal Gmail, or the Workspace admin has blocked third-party app access. Use the direct IMAP upload for a personal account; ask the admin to allow the tool for Workspace.
Do this: They were over 25 MB, they sat in Junk or Deleted Items which were unticked or the date filter cut them. Read the skipped list in the log, then run a second pass with Migrate only new data and the filters widened.
Have a PST and a Gmail address and not sure which route fits? Tell our support team the PST size, whether Outlook is installed and whether the account is Workspace or personal. We will point you at the fastest route.
PST to Gmail questions
About This GuideWritten and maintained by Leena Taylor Paul and the Univik team, developers of Windows data conversion and recovery software since 2013. The GWMMO and GWMME behaviour, Gmail bandwidth limits and storage figures in this guide were checked against Google Workspace Admin Help. Last verified September 7, 2026. Need a hand? Contact our support team.
Sources checked: Google Workspace Admin Help, About Google Workspace Migration for Microsoft Outlook · Google Workspace Admin Help, Migrate data from PST files (GWMME) · Google Workspace Admin Help, Gmail bandwidth limits · Google Workspace Admin Help, Troubleshoot an Outlook migration (25 MB limit, labels) · Google, Storage and upload limits for Google Workspace