The short answer: a simple planner is the one you’ll still open in a month. That usually means three things: little to set up, little on the screen, and no guilt when something waits a day. The five apps below are simple in different ways, so pick by the kind of simple you want.

A note first: we make Composed, one of the five. Every detail about another app comes from its own App Store listing or its maker’s pricing page, and each card links to its source. We say where Composed fits and where it doesn’t.

Three kinds of simple

  • Nothing to set up. Apple Calendar and Reminders are already on your phone. Microsoft To Do is free, and its My Day list suggests tasks for the day.
  • Nothing extra on screen. Things 3 is built around two lists, Today and Upcoming.
  • Nothing to fill in. Some apps take a sentence instead of a form. In Composed you say “dentist Thursday at 2pm” and it becomes an event with reminders.

The quick pick

  • Free, already installed: Apple Calendar and Reminders.
  • Free, with nothing to buy at all: Microsoft To Do.
  • A calm list you pay for once: Things 3, $9.99 for iPhone.
  • Your day as one timeline: Structured.
  • Plans you say out loud, with a time to leave: Composed.

Every option, compared

Apple Calendar + Reminders by Apple

What it is
The two apps already on your iPhone. Calendar shows your iCloud, Google and Exchange calendars together, and can show, create and complete your scheduled reminders
Free
Everything, already installed
Paid
Nothing to buy
Runs on
iPhone, iPad, Apple Watch, Mac
Good for
Starting with no download. Add a location to an event and Calendar tells you when it is time to leave
Worth knowing
Reminders only appear in Calendar after you select Scheduled Reminders in the calendar list

Microsoft To Do by Microsoft

What it is
To-do lists with My Day, a daily list it suggests tasks for
Free
Everything. The listing shows no in-app purchases and says "To Do is free and available on all your devices"
Paid
Nothing to buy
Runs on
iPhone, iPad, Apple Watch
Good for
A free daily list, especially if your work runs on Outlook
Worth knowing
It is a list app. Your calendar stays in another app

Things 3 by Cultured Code

What it is
A to-do app built around Today and Upcoming lists, with projects and areas
Free
No free version on iPhone
Paid
$9.99 once for iPhone and Apple Watch, with no in-app purchases. The Mac, iPad and Vision Pro apps are sold separately
Runs on
iPhone, Apple Watch
Good for
Paying once and owning it: a polished to-do list that also shows your calendar events
Worth knowing
Each device family is its own purchase

Structured by unorderly

What it is
Your day as one visual timeline that you drag tasks onto
Free
The timeline planner, an inbox, sub-tasks and notes, a Pomodoro focus timer, widgets, and sync across your Apple devices
Paid
Structured Pro adds calendar and Reminders import, recurring tasks, AI day planning and automatic replanning. Monthly or yearly subscription, or $99.99 once
Runs on
iPhone, iPad, Mac, Apple Watch
Good for
Time blocking: seeing the whole day in order, hour by hour
Worth knowing
Connecting your calendars and repeating tasks are both part of Pro

Composed by us

What it is
A planner you talk to: say or type a plan, or snap a screenshot of a booking, and it becomes an event with reminders, prep when the event calls for it, and a time to leave
Free
Every feature, for up to 5 active items you add yourself. Events imported from Apple Calendar or Google Calendar do not count
Paid
Pro removes the 5-item limit: $5.99 a month, $39.99 a year with a 7-day free trial, or $199 once
Runs on
iPhone
Good for
Appointments, trips and occasions you want to arrive at prepared and on time
Worth knowing
No projects, tags or priority levels, and no Android, iPad, Mac or web version

Other apps' details come from their own App Store listings and their makers' pricing and product pages, checked October 14, 2026. Prices are US prices. Prices and features change; the maker's page is the final word.

About “calm”

Calm is partly a feeling, and we can’t check feelings against a source. So here is only what we can say for certain about our own app. Composed has no red alerts and no overdue labels. Something that has waited a while is described plainly, not flagged. Its free plan holds 5 active items you add yourself, and events imported from Apple or Google Calendar don’t count toward them.

For the other four apps, judge the feel yourself. Every one of them is free to try: Apple’s apps and Microsoft To Do cost nothing, Structured’s free version includes its timeline, and Things 3 is a one-time $9.99.

Where Composed is the wrong pick

  • You want the fewest features possible. Microsoft To Do or Apple Reminders will be simpler. Composed adds reminders, prep and a time to leave to your events.
  • You plan on an iPad or a Mac. Composed is iPhone only.
  • You organise by projects and tags. Composed has neither. Things 3 has projects and areas.

FAQ

What is the simplest planner app for iPhone?

Apple Reminders and Calendar, because there’s nothing to install or set up. Calendar can show your scheduled reminders beside your events. Open Calendar, tap Calendars, and select Scheduled Reminders.

Is there a planner app that doesn’t make you feel behind?

That comes down to how an app shows things you haven’t done yet, so try a few. Composed was designed around this: no red alerts, no overdue labels.

Which simple planner has no subscription?

Apple Calendar and Reminders and Microsoft To Do are free. Things 3 is $9.99 once for iPhone. Composed Pro can be bought once for $199, and its free plan needs no purchase.