The best planner apps that sync between Windows and Mac, and which ones work offline

The best planner apps that sync between Windows and Mac today are the account-based task apps: Todoist, TickTick, Microsoft To Do and Amazing Marvin. Each keeps your lists in an online account, so a task you add on a Windows laptop shows up on a Mac once both are signed in. They differ in how much works without a connection and in what happens when you change the same task on two computers. Barside goes the other way. It's a free, offline-first planner that keeps your tasks in notes on your own computer, on Windows, Linux and Mac.

We make Barside, so this page says plainly where another app will suit you better. If you need one planner on a Windows computer and a Mac, and sync between computers needs Barside Plus. Features and plans change, so every comparison points to the vendor's own page, as of October 2026.

What should you check before trusting a cross-platform planner?

Most lists of the best cross-platform planner apps for Windows and Mac in 2026 stop at a row of logos. A logo tells you an app exists on a system, but it says little about how the app behaves there. Four questions decide whether a planner will hold up when you move between computers.

• A desktop app built for the system, or a web page in a window. Some desktop apps are built for the system, and some wrap the web app in a window. A wrapper can be perfectly good, but it often leans on the network more, and it may ignore system shortcuts or the tray.
• Offline use. Can you open the app on a train, add three tasks, tick two and close it without losing anything? Some apps keep a full copy on your computer, some keep a partial one, and some need the connection to show anything at all.
• Edits on two computers. Say you rename a task on the Mac while the Windows laptop is offline, and change its date on the laptop. Which edit survives when both reconnect? Vendors rarely answer this on their home pages.
• A phone too. Most people who plan across two computers also want the list on a phone. Account-based apps usually cover this, and a desktop-only planner doesn't.

Which planner apps are best for syncing between Windows and Mac?

The best cross-platform planner apps for Windows and Mac sync in 2026, among them Todoist, TickTick, Microsoft To Do and Amazing Marvin, all work the same basic way: your tasks live in your account and each device keeps a copy. The table sums up what each one is built for and where to confirm its current apps and plans. We've left out any offline or conflict behavior we couldn't confirm on an official page, so run the test in the next section on any app you shortlist.

Todoist

Todoist is a polished list with projects, due dates and a free plan alongside paid plans. It has phone apps and keeps your lists in your account, which makes it a safe default for someone who plans at a Windows desk and on a MacBook. Check its pricing page to see which features, such as calendar views or reminders, come with the free plan.

TickTick

TickTick pairs a task list with a calendar view, so it suits people who like to see tasks laid out on days and hours. It has phone apps as well. Look at its upgrade page for what the free tier includes before you plan your week around a paid view.

Microsoft To Do

Microsoft To Do is free and tied to your Microsoft account, with lists, My Day and reminders. If you already spend your workday in Outlook, it adds the least friction of the four. It's more a list than a planner, so pair it with a calendar if you time block.

Amazing Marvin

Amazing Marvin is built for people who want to tune their planning system, switching features on and off until it fits how they work. It suits tinkerers, and people who found simpler lists too rigid. Check its site for the current apps and plans on each system.

Barside

Barside is a free desktop app where every checklist item in every note is a task, with a read-only view of up to 10 Google, Outlook or other iCal calendars beside them. It works offline first: your notes and tasks are saved on your computer, and you don't need an account. Sync between computers comes with Barside Plus. It runs on Windows, Linux and Mac, and there's no phone app.

How to test offline use and two-computer sync in ten minutes

Vendor pages describe the happy path, so before you move a year of tasks into any planner, run this test on both computers with a throwaway list. It tells you more than any review.

1. Install the desktop app on both computers and sign in. Note whether it opens in its own window with system menus and shortcuts, or looks exactly like the website.
2. Create a list called Sync test with three tasks, and wait until all three appear on the second computer.
3. Turn off Wi-Fi on the first computer. Close the app, reopen it and see whether your tasks are still there.
4. While offline, add a task, tick one and change the date of another.
5. On the second computer, still online, rename the task whose date you changed.
6. Turn Wi-Fi back on and wait a minute. Check both computers: did the new task arrive, did the tick hold, and did the task keep both the new name and the new date?
7. Delete the Sync test list.

If step 3 shows an empty screen or a sign-in page, the app needs the network before you can plan. If step 6 lost one of the two edits, you know to finish changes on one computer before you pick up the other.

What happens when you edit the same task on two computers?

With the best planner apps for Mac and Windows sync, the edge case worth understanding is the conflict: the same task changed in two places before the two copies have talked to each other. Planners settle it in one of three general ways, and the test above shows you which one an app uses.

• The latest change wins. The whole task takes the version saved last. It's simple, and it can quietly drop the other computer's edit.
• Changes merge field by field. A new name from one computer and a new date from the other both survive, because they touched different parts of the task.
• Both versions are kept. The app saves a copy and asks you to choose. Nothing is lost, though you tidy up by hand.

Two habits avoid most conflicts. Let a computer show that it has synced before you close the lid, and do your daily plan on one machine while the other only reads it. A shared calendar helps too. If your time blocks are Google Calendar or Outlook events, the calendar company keeps them in step on every device, and your planner only has to hold the task list.

Which planners work offline and sync later?

The best offline daily planner apps for a Windows computer and a Mac that sync later keep the full plan on the device first and treat the cloud as an extra. That's how Barside is built. The calendar view, the task board, reminders and the daily briefing are worked out on your computer from what you saved, so they work with no network and no account.

Your calendar is the one part that needs a connection to change. Barside downloads each connected calendar every 15 minutes, when it starts, and after your computer wakes or unlocks. Offline, you see events as of the last refresh, and Barside catches up when you reconnect. Google decides how fast a change reaches the calendar's iCal address, and that can take hours.

To carry your plan to a second computer, Barside Plus adds sync between computers and cloud backup, at US$20 a month or US$200 a year. Cloud sync isn't end-to-end encrypted, so decide what belongs in a synced workspace. The guide to syncing notes between computers covers the options with and without the cloud, and the local-first app with private backups guide explains how backups work. If offline-first matters most to you, the list of the best local-first apps compares other tools built the same way.

How to set up Barside as your daily planner

On Windows, Linux or Mac, you can have a working planner in a few minutes.

1. Download Barside and open it.
2. Open Settings & backups, scroll to Calendars and choose Add calendar. Under Where do I find it?, pick Google Calendar, Outlook or Other, and follow the button that opens the right settings page.
3. Paste the address into Secret iCal address and choose Check address. Barside tells you how many events it found in the next 30 days. Name the calendar, pick a color and choose Add calendar.
4. Make a plan note from the free daily planner template, or write your own with a checklist. Give items a date with + date and they land on the task board under Overdue, Today, Tomorrow, Next 7 days, Later or No due date.
5. Press the bell at the end of a checklist item to set a reminder at an exact time. When it fires, clicking it opens the note at that line.
6. Each morning, open Library & briefing and the Daily briefing tab to see today's calendar, due reminders and unchecked tasks on one page.
7. Turn on Start with Windows in Settings (it's called Open at login on Linux, and in Barside for Mac) so reminders fire while Barside sits in the tray.

To keep the plan in view, pin the note to your desktop in its own window, or dock it to the screen edge, where it folds into a slim tab. Press Alt+Shift+Space in any app and type cal for the calendar, brief for the briefing, or task and a few words to add a task without leaving what you're doing.

How different people plan across their computers

• A developer with a Windows desktop at work and a MacBook at home keeps her tasks in Todoist for now, because it covers both computers and her phone. Her meetings live in Outlook, which every device already shows. She's trying Barside for Mac.
• A freelance writer who works on a Windows laptop in cafes with patchy Wi-Fi plans in Barside. Her drafts, client checklists and reminders are on the laptop, so a dropped connection changes nothing, and her two Google calendars show in one agenda in their own colors.
• A Linux user with two computers runs Barside on both and uses Barside Plus to sync them. He plans the day on his desktop each morning and only ticks items on the laptop, so the two rarely edit the same task.
• A team lead clicks Meeting note on each calendar event. The note arrives with the time, the people and an Action items checklist, and those items appear on the task board. See the calendar next to your notes.

What Barside doesn't do

• A Windows and Mac pair. Barside runs on Windows, Linux and Mac. For a Windows and Mac pair, an account-based app may still be the practical choice.
• No phone app. Barside is a desktop app. Time blocks you create as Google Calendar or Outlook events still reach your phone through those apps.
• Read-only calendar. Barside never adds, moves or deletes events, so you schedule in Google Calendar or Outlook. If you want a planner that writes blocks for you, read AI planner apps that auto schedule tasks.
• No timer. Use a separate timer inside a block if you like countdowns; the time blocking guide shows how to plan without one.
• Sync needs Plus. Sync between computers is part of Barside Plus, and it isn't end-to-end encrypted.

Where your plan is stored

Without Plus, your notes, tasks and reminders are saved in Barside's data folder on your computer, and you don't need an account. The private calendar address you paste is stored encrypted on your computer and left out of backups, and your calendar is downloaded straight from Google or Microsoft. Anyone with that address can read the calendar, so keep it private and reset it in your calendar app if it leaks. Read how calendar feeds are stored.

Account-based planners such as Todoist and Microsoft To Do keep your lists in your account, which is exactly what lets them follow you across devices. So the choice comes down to which you value more: having the list on every device, or having it on your own computer first. For more options, the guide to the best free daily planner apps that sync with Google Calendar compares planners by their calendar sync.

Other parts of planning in Barside

The calendar is one part of planning in Barside. These guides cover the rest.