Proton Calendar

Proton Calendar is a calendar app for Android and iOS, with event management, scheduling links, shared calendars and video meeting support. Users can create, edit, delete and manage recurring events and invitations, then receive notifications on mobile devices or desktop browsers. Appointment scheduling updates availability and adds confirmed meetings, while Proton Mail integration lets users send invitations and add events from their inbox. Event titles, descriptions, locations and invited people receive end-to-end or zero-knowledge encryption. A free Proton account includes up to three calendars and is listed as free. Paid Proton Mail plans allow up to 25 calendars and add sharing by link with other calendar services on the web; calendar import and export are also available on paid plans. Proton is incorporated and headquartered in Switzerland, where it follows Swiss privacy laws. Subscriptions bought through proton.me renew automatically, and users can switch plans at any time; upgrades receive prorated credit.

Proton Calendar combines encrypted event details with scheduling and Proton Mail integration. Its free plan covers up to three calendars, while larger calendar limits and some sharing features require a paid plan.

It suits people who want encrypted calendar details, mobile access and scheduling features. Those who need more than three calendars or paid-plan sharing and import/export will need a paid Proton Mail plan.

Proton Calendar is a privacy-focused calendar for people who want event details encrypted and everyday scheduling connected to Proton Mail. It is especially well suited to Proton Mail users, though its free plan’s three-calendar cap and paid-only sharing and import/export limit its flexibility.

Its strongest reason to choose it is the protection of event details; its clearest compromise is that useful collaboration and portability features require a paid Proton Mail plan.

Overview

Proton Calendar covers recurring events, invitations, and notifications on mobile devices or desktop browsers. End-to-end or zero-knowledge encryption protects event titles, descriptions, locations, and invited people, a meaningful advantage for users who do not want those details exposed to the calendar provider. Proton is incorporated and headquartered in Switzerland and follows Swiss privacy laws.

Mail integration lets users send invitations and add events directly from Proton Mail. That makes the calendar a practical fit for people already using Proton’s mail service, but less compelling for those who want a standalone calendar with broad two-way syncing: calendar sync is one-way.

Key features

Appointment scheduling automatically updates availability and adds confirmed meetings, reducing manual upkeep when coordinating appointments. Scheduling links and video meeting support help it serve beyond basic personal event tracking. Users can create, edit, delete, and manage recurring events and invitations, with notifications through desktop browsers or mobile devices.

Paid users can share calendars via links with other calendar services on the web, and can import and export calendars. Those features make paid plans more practical for people coordinating across services or moving calendar data; the free tier is more limited for collaboration and portability.

Pricing

The Free plan costs nothing and includes essential Proton Calendar features with a free Proton account, up to three calendars. That is enough for a modest personal setup, but users who need more calendars, sharing, or import/export will need a paid Proton Mail plan.

Mail Plus and Unlimited each support up to 25 calendars for one user. Their prices are custom pricing. Paid Proton Mail subscribers get additional calendar features, but the free plan is the only option with a published price in these tiers. Subscriptions bought through proton.me renew automatically; users can switch plans at any time, and upgrades receive prorated credit.

Platforms

Proton Calendar has mobile apps for Android and iOS. Notifications are also supported through desktop browsers, though the listed platform support is limited to Android and iOS.

Who it's for

Choose Proton Calendar if encrypted event details matter, you already use Proton Mail, and three calendars are sufficient on the free plan. It also suits paid subscribers who need up to 25 calendars and web-link sharing. Look elsewhere if two-way calendar sync is essential, or if you need sharing and import/export without paying.

Pros and cons

• Pro: Encryption covers titles, descriptions, locations, and invitees, protecting the details that can reveal the most about an appointment.
• Pro: Proton Mail integration lets users send invitations and add events directly from mail, reducing friction for existing Proton users.
• Pro: Scheduling automatically updates availability and adds confirmed meetings, useful for appointment-based coordination.
• Con: The free plan allows only three calendars and excludes paid sharing and import/export, which constrains heavier users.
• Con: Calendar sync is one-way, making it a weaker fit for workflows that depend on changes syncing in both directions.
• Con: Mail Plus and Unlimited have custom pricing, so their costs cannot be compared from the published plan prices.

Alternatives

Microsoft Outlook Calendar is a better fit for users who want calendar support across Android, iOS, macOS, and web; Microsoft 365 Personal, Family, and Premium offer a one-month free trial.

Zoho Calendar suits individuals or teams seeking a free online calendar with one appointment booking link for each free user.

Lark is an alternative for users who want a broader platform with Android, iOS, desktop, web, and API support; its Starter plan lists 20 users, 100 GB storage, 18 months of message history, and 1,000 monthly automations.

Calendar.com offers a free plan for individuals and a Standard plan starting at $20 a month, making it an option for readers comparing a free individual tier with a paid plan.

Tuta Calendar is another privacy-oriented calendar choice, with a free plan limited to one calendar and a Revolutionary plan at €3 a month.

Teamup may suit users who need a free shared setup with five sub-calendars and five users, plus one custom field and one year of historical data.

Cozi is an alternative for families looking for a shared calendar alongside grocery and to-do lists and a recipe library on its free tier.

TimeTree is another calendar option for people who want shared calendars with comments and photos.

For a broader shortlist, browse Calendar apps.

Verdict

Proton Calendar is the right choice for people who put privacy first and already rely on Proton Mail, especially if three calendars cover their needs or they are comfortable with a paid plan for sharing and portability. Its encrypted event details and scheduling are the main draw; look elsewhere if you require two-way syncing or want paid-tier collaboration features on a free plan.