macOS menu bar · Free & Open Source

Your calendar,
that remembers you.

Calen is an AI calendar companion for macOS that learns your patterns, integrates with Google Calendar, and helps you plan — through natural conversation.

Download for macOS View on GitHub
macOS 14+ Sonoma Apple Silicon & Intel Signed & Notarized MIT License · Free
Calen app screenshot

Why Calen

Everything you need,
nothing you don't.

Built for developers and creators who live in their calendar — and want AI that actually understands them.

🧠

Hermes Long-Term Memory

Learns your preferred time blocks, energy patterns, and scheduling habits over time. Gets smarter the more you use it.

AI Planning Actions

Reschedule your day, fill empty slots, auto-categorize events — all through a natural chat interface in your menu bar.

🔗

Unified Calendar View

Google Calendar + Apple Calendar side by side. Todos, reminders, and AI suggestions — one place to see it all.

Instant Menu Bar Access

No windows. One click from your menu bar and your full calendar is there. Close it and it's gone.

🎯

Smart Habit Tracking

Set range-based habits that span days or weeks. Visual progress bars on your calendar grid keep you accountable.

🔒

Private by Default

Your data stays on your Mac. API keys are in your Keychain. No server collects your calendar data — ever.

Deep Dive

Built different.

Hermes Memory

An AI that knows your patterns

Most AI assistants forget everything after a session. Hermes is different — it extracts long-term insights from your conversations and applies them automatically.

  • Detects preferred focus blocks and energy cycles
  • Remembers recurring context ("every Mon is standup")
  • Applies insights silently to future scheduling
Calen full view
AI Chat

Just talk to your calendar

Type in plain language. Calen understands what you mean and takes action — creating, moving, or restructuring your day.

  • "Move my 3pm to tomorrow morning"
  • "Fill my afternoon with deep work blocks"
  • "What's free this week for a 2-hour focus session?"
Calen AI chat
Review Tab

Know how you spend your time

Weekly stats, habit streaks, and completion rates — the Review tab turns your calendar into a personal productivity dashboard.

  • 7-day completion bar chart
  • Year-long habit grass grid
  • AI-generated weekly retrospective
Calen review

Interactive Demo

See it in action.

리뷰
☀ Today's Adjustment
Apr 21, 2026
7-Day Progress
Wed
Thu
Fri
Sat
Sun
Mon
Today
30-Day Todo Tracker
Best day 14/14 | Streak 0 days
Long-term Goals
⭐ calen 5만 달성!
올해
Habit Adherence
캘린 하루 1커밋
5%
🗨 April
4월 22일 수요일
D-1
팀 스탠드업
10:00–10:30
코드 리뷰 세션
15:00–16:00
+ 할 일 추가
오늘
이번주
이번달
올해
1 / 1 할일 달성률
100%
7-Day Progress
Wed
Thu
Fri
Sat
Sun
Mon
Today
30-Day Tracker
최대 완료일 14/14 | 연속 완료 0일
Habit Adherence
캘린 하루 1커밋
5%
습관 달성률 — 캘린 하루 1커밋
W1
W2
W3
W4
오늘의 할일
배포 체크리스트 작성 (플렉)
AI
+ Claude
⚙ Codex
🗑
캘린 배포를 위한 2주완성플랜을 만들어서 등록해줘
저녁 집중 흐름을 기준으로 2주 배포 플랜을 등록할게요. 1주차는 정리·연동·검증, 2주차는 안정화·배포·회고 순서로 잡겠습니다.
🔧 할일 추가: 배포 범위 확정 (플렉)
🔧 할일 추가: 배포 체크리스트 작성 (플렉)
🔧 할일 추가: 구글캘린더 연동 점검 (플렉)
🔧 할일 추가: 핵심 시나리오 테스트 (플렉)
···

Setup

Up in 3 minutes.

No configuration files. No signup. Just install and connect.

STEP 01

Install via Homebrew or .dmg

Download the universal binary or use Homebrew Cask. Signed and notarized — no Gatekeeper warnings.

$ brew tap oyeong011/calen
$ brew install --cask calen-ai
STEP 02

Connect your Google Calendar

One-click OAuth flow. Calen only asks for the scopes it needs. Your credentials stay in your Keychain.

# Scopes used:
calendar.events
calendar.readonly
STEP 03

Add your AI key & start chatting

Paste your Claude or OpenAI API key in Settings. Then ask Calen anything — it handles the rest.

# Settings → AI Provider
Claude (Anthropic) ✓
OpenAI / Codex ✓

Pricing

Simple, honest pricing.

No subscriptions. No paywalls. No telemetry.

Free
Forever · Open Source · MIT License
  • Full calendar + AI chat
  • Hermes long-term memory
  • Google + Apple Calendar sync
  • Habit tracking & review analytics
  • Automatic updates via Sparkle
  • Source code on GitHub
Download Calen
Latest: v0.4.x · Universal · Signed & Notarized

Start scheduling smarter.

Your calendar is already full. Let Calen help you make it intentional.

Homebrew ● tap available
$ brew tap oyeong011/calen
$ brew install --cask calen-ai