# Alternatives to Proton Calendar E2E encrypted calendar. Proton Calendar ranks #8 of 8 in Calendar apps, with an Alt Score of 42. It is licensed under GPL-3.0, freemium from €3.99/mo and available on iOS, Android and Web. 7 of 10 checklist rows are verified against a public source. Source: https://altcatalog.com/alternatives/proton-calendar/ Category: Calendar apps ## Where Proton Calendar stands out - **Open source** — 1 of 7 apps with a verified answer have this ## Overview - **Who it's for**: Individuals and businesses who want to keep their schedules and event details private, from personal users to teams needing GDPR/HIPAA-compliant collaboration. - **What you get**: A fully encrypted calendar where event titles, descriptions, locations, and invitees are protected end-to-end (with zero-knowledge encryption for events from non-Proton calendars). It integrates directly with Proton Mail for invitations and event creation, supports shared/team calendars, and is available on web, iOS, Android, macOS, Windows, and Linux. - **How it works**: Users create and manage events through the Proton Calendar app or directly within Proton Mail; invitations, RSVPs, and updates sync automatically while all event data stays encrypted, hosted under Swiss privacy law. ## Profile - **License**: GPL-3.0 (verified 2026-07-10) - **Pricing model**: Freemium (verified 2026-07-10) - **Starts at**: €3.99/mo (verified 2026-07-10) - **Platforms**: iOS, Android, Web - **Status**: active (verified 2026-07-10) ## Ranked alternatives | # | App | Alt Score | Licence | Platforms | |---|-----|-----------|---------|-----------| | 1 | [Google Calendar](https://altcatalog.com/alternatives/google-calendar.md) | 78 | Proprietary | Web, Android, iOS | | 2 | [BusyCal](https://altcatalog.com/alternatives/busycal.md) | 73 | Proprietary | macOS, iOS | | 3 | [Fantastical](https://altcatalog.com/alternatives/fantastical.md) | 73 | Proprietary | Windows, macOS, iOS | | 4 | [Amie](https://altcatalog.com/alternatives/amie.md) | 68 | Proprietary | Windows, macOS, Linux, iOS | | 5 | [Morgen](https://altcatalog.com/alternatives/morgen.md) | 68 | Proprietary | Windows, macOS, Linux, iOS | | 6 | [Apple Calendar](https://altcatalog.com/alternatives/apple-calendar.md) | 64 | Proprietary | macOS, iOS, Web | | 7 | [Notion Calendar](https://altcatalog.com/alternatives/notion-calendar.md) | 60 | ? | Windows, macOS, iOS, Android | Alt Score = Verified coverage (90%) + Visibility (10%). See https://altcatalog.com/how-alt-score-works/ ## Feature comparison Legend: Yes / No / Partial / ? (not verified). | Calendar apps checklist | Proton Calendar | Google Calendar | BusyCal | Fantastical | Amie | Morgen | |---|---|---|---|---|---|---| | Pricing model | Freemium | Freemium | One-time | Freemium | Freemium | Subscription | | Starts at | €3.99/mo | €6.80/user/month | $49.99 | ? | $6/mo | $10/seat/mo | | License | GPL-3.0 | Proprietary | Proprietary | Proprietary | Proprietary | Proprietary | | Platforms | iOS, Android, Web | Web, Android, iOS | macOS, iOS | Windows, macOS, iOS | Windows, macOS, Linux, iOS, Web | Windows, macOS, Linux, iOS, Android, Web | | Accounts supported (Google, CalDAV, Exchange) | Partial | Partial | Yes | Yes | Partial | Partial | | Natural language event entry | ? | Yes | Yes | Yes | Yes | Yes | | Scheduling links built in | ? | Yes | ? | Yes | Yes | Yes | | Tasks integration | No | Yes | Yes | Yes | Yes | Yes | | Menu bar / widgets | ? | Yes | Yes | Yes | Yes | Yes | | Time zones handling | Yes | Yes | Yes | Yes | Yes | Yes | | Offline | No | Yes | Yes | ? | ? | ? | | Open source | Yes | No | No | No | No | No | | One-time purchase option | No | No | Yes | No | No | No | | Team scheduling | Yes | Yes | ? | Yes | Yes | Yes | ## Sources Sources for Proton Calendar. Each alternative is sourced on its own page. - **Starts at**: €3.99/mo — (verified 2026-07-10) - Quote: “€47.88 for one year (€3.99/month)” - **License**: GPL-3.0 — (verified 2026-07-10) - Note: spdx_id": "GPL-3.0"" — Proton's web clients (incl. Calendar) are published under GPL-3.0. - **Platforms**: iOS, Android, Web — (verified 2026-07-10) - Note: Dedicated Calendar apps are iOS/Android plus the web app at calendar.proton.me; desktop access is via the bundled Proton desktop app. - Quote: “Download Proton Calendar for Android & iOS” - **Pricing model**: Freemium — (verified 2026-07-10) - Note: Free tier includes personal calendars; paid Proton plans add more. - Quote: “3 personal calendars” - **Status**: active — (verified 2026-07-10) - Note: pushed_at": "2026-07-10T08:16:35Z"" — WebClients repo pushed the day of research. - **Accounts supported (Google, CalDAV, Exchange)**: Partial — (verified 2026-07-10) - Note: Only Google import (Easy Switch) and ICS import/subscription; no CalDAV, no Exchange. - Quote: “Proton Calendar doesn't support CalDAV, so you can't set up a direct two-way sync with an external calendar.” - **Tasks integration**: No — (verified 2026-07-10) - Note: Tasks are listed as a much-requested feature still in development, i.e. not yet available. - Quote: “a faster and more stable next-generation calendar app for both iOS and Android to support much-requested features like tasks, search capabilities, and offline access” - **Time zones handling**: Yes — (verified 2026-07-10) - Quote: “To change the time zone the event occurs in, click Show time zones and change the settings as required.” - **Offline**: No — (verified 2026-07-10) - Note: Offline access is listed as a much-requested feature still in development. - Quote: “a faster and more stable next-generation calendar app for both iOS and Android to support much-requested features like tasks, search capabilities, and offline access” - **Open source**: Yes — (verified 2026-07-10) - Note: spdx_id": "GPL-3.0"" — Proton's clients are published under GPL-3.0 in the ProtonMail/WebClients repository. - **One-time purchase option**: No — (verified 2026-07-10) - Note: Recurring subscription plans only; no perpetual licence. - Quote: “€47.88 for one year (€3.99/month)” - **Team scheduling**: Yes — (verified 2026-07-10) - Quote: “Check everyone's schedule at a glance” --- Ranked by verified data, never by who paid. https://altcatalog.com/trust/