Apple's Reminders app is great, but I've always wanted to add its entries to my iPhone's Calendar app, too. I am at my most productive when I have a to-do list with deadlines clearly listed, but I find it overwhelming to look at that list at the start of the day. I used to dread adding too many entries to Reminders until I discovered ReminderCal ($5). This app does one job and does it well—sync reminders with the Calendar app.
Why I like seeing my tasks in Calendar
The Calendar app has a neat week view that adds a bit of space between every entry. If I have a run at 5am, meditation at 7, and work at 9:30, these entries seem overwhelming in Reminders. In the Calendar, the same three entries appear vertically with long gaps in between, which tells me that I have lots of free time in between my tasks. It's almost like a trick that reduces the urgency of tasks and makes my brain think: "I can do this!"
How to sync Reminders with Calendar
Once you download and install ReminderCal on your iPhone, iPad, or Mac (a single purchase unlocks the app on all three platforms), you'll need to give it access to your calendars and to the Reminders app. From here, the app will do its job with minimal input.
Now, when you add timed reminders in Apple's Reminders app, they'll start appearing in the Calendar automatically. If there are reminders that you don't want to sync, you can start those entries with $nocal or $nocalendar and ReminderCal will ignore them.
On Mac, as long as you let ReminderCal run in the background, it'll automatically sync all your tasks. You don't need to keep opening it and hitting the sync button.
On iPhone and iPad, background syncing is less reliable due to battery saving measures in the operating system. That's why I suggest using Apple's Shortcuts app to set up an automation to force a sync at a fixed interval. Just open the Shortcuts app, click the "+" in the top-right corner, select a time of day for the Shortcut to activate, tell the shortcut to activate daily, and choose the ReminderCal option. If you want ReminderCal to run multiple times a day, you'll have to set up a few different automations to force it to run every few hours.
Personally, I like to plan my day in advance, so I've set ReminderCal up to automatically sync at sunrise. When I add tasks for the same day, I can always open ReminderCal on my iPhone and sync it manually. It takes a second for the entries to appear in the calendar.
Configuring ReminderCal to your liking
I like ReminderCal's simplicity, and that shows in its settings menus as well. The default options are great for almost everyone, but you can change a few things if you like. The app allows you to choose if you want repeating reminders to appear in your calendars, for example. It's enabled by default but you can disable it if you want to. You can also force the app to sync completed reminders that were due in the past, but this is disabled by default to avoid cluttering your calendar.
There are two tweaks I suggest. I changed the default event duration to one hour from 30 minutes. The second tweak lets you invert the $nocal exception phrase. If you enable it, ReminderCal will only sync those reminder entries that have the $nocal phrase in the body. This is a good option for those who want to be very selective with syncing reminders with the calendar.
A limitation that you should be aware of
Unfortunately, third-party apps often have to deal with restrictions. ReminderCal cannot sync your reminders to calendars other than Outlook and iCloud. That's going to be a dealbreaker for lots of people, especially those who rely on Google Calendar, but there's nothing the app's developer can do about this as of yet.