There's no official sync between Google Tasks and Microsoft To Do. If your life spans both — Gmail and Google Calendar on one side, Outlook and Teams on the other — you've probably resorted to maintaining the same tasks in two places, or just letting one of them go stale.
This guide shows you how to keep them in a seamless two-way loop: change something on either side, and it shows up on the other. Free, open-source, no subscription, and your task data never passes through a third-party server.
What gets synced
Everything you'd expect from a real two-way sync:
- Titles, notes, due dates (with time reminders)
- Completion status — check it off anywhere, it completes everywhere
- Lists, subtasks, moves between lists, and deletions
- Edit on either side; both sides stay identical
Sync runs automatically in the background every 10 minutes.
The 3-step setup (Windows)
- Download the installer from the project website and run it — no terminal, no commands.
- Follow the setup wizard. It walks you through connecting Google Tasks and Microsoft To Do (personal Microsoft accounts take the easy path).
- Done. A sync panel shows status and settings any time you want to check.
That's it. Your tasks start syncing in the background.
Mac and Linux users: see the website for the command-line install.
Why this instead of a paid sync service
- Free forever. MIT-licensed open source. No subscription, no per-task pricing, no "pro" tier holding your data hostage.
- Private by design. It runs entirely inside your own Google Apps Script project. No third-party server ever sees your task lists.
- It doesn't guess. When the two sides disagree ambiguously, the sync parks the conflict for your review instead of silently overwriting. Deletions take two rounds to confirm, so a misclick doesn't nuke your list.
Good to know
- Capacity: comfortably handles around 300 task pairs; stress-tested to 600.
- Microsoft account type: the wizard's easy path works with personal Microsoft accounts. Work or school accounts use the self-managed Entra setup in the deployment guide.
- Cost: $0. It runs on Google's free Apps Script quota.
Links
- Website & download: https://simonchai-tw.github.io/tasks-todo-sync/
- Source code (GitHub, MIT): https://github.com/simonchai-tw/tasks-todo-sync
Disclosure: I'm the author of this tool. It's my own open-source project, and this post is a how-to, not an ad — the code is public and you can inspect everything it does.
