Skip to content
ToolGPA

One Calendar

One view of all your calendars on Android, Apple and Windows

Free plan · from $5.99 one-timeCalendarChecked Oct 9, 20264.8 on the App Store
Visit onecalendar.nl

What is One Calendar?

One Calendar, written OneCalendar on its own site, is a calendar app from the Dutch company Code Spark for Android, iPhone, iPad, Mac and Windows. It connects directly to accounts such as Google, Outlook, Office 365, Exchange, iCloud, Yahoo, Nextcloud and other CalDAV servers and shows them in one overview with day, week, month, year and list views. The app is free, and a one-time Premium license adds search, theming, appointment colors and a longer history.

One Calendar has a free plan. Paid plans start at $5.99 one-time per platform (App Store or Google Play). See every plan

Good for

  • People who mix Google, Microsoft, iCloud and CalDAV calendars
  • Households or workers split between Android, iPhone and Windows
  • Buyers who want a one-time payment and no subscription

Worth knowing

  • A Premium license is needed per platform group: Android, iOS and Windows are each bought separately, because the stores do not allow cross-platform licensing.
  • The free version syncs 6 months of past appointments and leaves out search, theming and appointment colors.
  • The Microsoft Store page lists the Windows app as free with in-app purchases but does not show the Premium price.
  • No web or Linux version is listed. Printing and automatic day rollover are Windows-only Premium features.

Key features

Many calendar services in one app
Connects to Google Calendar, Outlook, Office 365, Exchange, iCloud, Yahoo, GMX, Synology, Nextcloud, ownCloud, Mailbox.org and other CalDAV servers, and shows them together.
Five views with week numbers
Day, week, month, year and list or agenda views, all with week numbers. A quick filter narrows what is shown by calendar color.
Appointments and invitations
Add, change and delete appointments, set up recurrences, invite people to a meeting and accept incoming invitations. Appointments can be shared through apps such as WhatsApp.
Works offline
Appointments can be viewed and managed without an internet connection, according to the vendor's feature list.
Widgets and live tiles
Several widgets are available depending on the operating system, including live tiles on Windows. Choosing which calendars, birthdays and tasks a widget shows is a Premium feature.
Theming and colors
Premium unlocks 170 color options, a background picture, a custom text color and predefined themes, plus a separate color for any single appointment. A dark theme is supported.

One Calendar pricing

Starts at
$5.99 one-time per platform (App Store or Google Play)
Free plan
Free version with all five views, appointment management and every supported calendar type, syncing 6 months of past appointments. Search, theming, appointment colors and widget configuration need Premium.
Free trial
None listed
Free$0Day, week, month, year and list views across all connected calendars, with invitations and recurrences and 6 months of past appointments.
Premium$5.99one-time payment per platform group (App Store or Google Play)Appointment colors, theming, search, 3 years of history, widget configuration, immediate sync and navigation. Windows needs its own license.

Read from apps.apple.com on Oct 9, 2026. Prices change, so confirm with One Calendar before you buy.

Pricing in detail

How people rate the One Calendar app

4.8

out of 5 for the iPhone and iPad app

20,678 ratings on the App Store in the United States, read Oct 9, 2026. It rates the app, not everything the product does. See the listing

One Calendar reviews, and where to read more

Works with

One Calendar alternatives

All One Calendar alternatives comparedAll calendar and scheduling apps

Common questions

Is One Calendar free?

One Calendar has a free plan. Free version with all five views, appointment management and every supported calendar type, syncing 6 months of past appointments. Search, theming, appointment colors and widget configuration need Premium. Paid plans start at $5.99 one-time per platform (App Store or Google Play).

How much does One Calendar cost?

One Calendar lists 2 plans. Free: $0. Premium: $5.99 one-time payment per platform group (App Store or Google Play). Prices were read from apps.apple.com on Oct 9, 2026.

What platforms does One Calendar work on?

One Calendar is available on Android, iOS, macOS and Windows.

How is One Calendar rated?

One Calendar's iPhone and iPad app averages 4.8 out of 5 from 20,678 ratings on the App Store in the United States, as read on Oct 9, 2026. That is the store's rating of the app, not a score from us.

Does One Calendar have a Linux app?

No Linux app was listed when its pages were read on Oct 9, 2026. One Calendar is listed for Android, iOS, macOS and Windows.

Is One Calendar open source?

One Calendar is not described as open source on its own site, as read on Oct 9, 2026.

Does One Calendar work offline?

Yes, according to its own site. What works without a connection differs by plan and platform, so check the vendor's page for the detail.

What does One Calendar integrate with?

One Calendar's listing names Google Calendar, Outlook, Office 365, Exchange, iCloud, Yahoo Calendar, Nextcloud and Synology. A listing names up to eight integrations, so it may connect to more.

Who makes One Calendar?

One Calendar is made by Code Spark.

What are the alternatives to One Calendar?

The closest alternatives to One Calendar in our directory are DigiCal, Business Calendar 2, CalenGoo, aCalendar and Google Calendar. Each one has a side-by-side comparison with One Calendar.

Sources for this page

The prices, plans, platforms and features above were read from these pages on Oct 9, 2026. What people say is linked where it appears.