Third Arm
Your central hub for notes, reminders, subscriptions, diary, habits, saved links, study timers, flash cards, images, and more.
Capture quickly from the menu bar, organize everything in one place, and upgrade only when you need more space or Pro+ API access for your own AI tools.
Download for MacOne app for everyday capture and tracking
Collect, organize, and manage your personal information across the categories you actually use, without jumping between separate apps.
Quick Notes
Capture ideas instantly and keep them synced across your account.
Diary
Write journal-style entries with optional titles and keep them organized over time.
Reminders
Set reminders in hours, days, weeks, months, or on a fixed date and time.
Habits
Track daily, weekday, or weekly routines and monitor your streaks.
Links
Save links with notes, mark them read or unread, and keep research in one place.
Subscriptions
Track recurring subscriptions with due dates, monthly plans, yearly plans, or custom durations.
Payments
Log one-off spending with simple title and amount tracking.
Study Timers
Run General or Focus Time sessions. Timers are unlimited and never counted toward your cap.
Flash Cards
Create and organize question-and-answer cards by category.
Images Pro
Store images locally with metadata and notes. Supported formats include JPG, PNG, HEIC, GIF, WebP, BMP, and TIFF.
Built for quick access
Menu Bar Quick-Add
Click the menu bar icon to add a Reminder, Habit, Link, Timer, Subscription, Diary entry, Flash Card, Payment, or Quick Note without opening the full app. There is also a built-in currency and unit converter for fast utility work.
Calendar View
See subscription due dates and reminders on a monthly calendar. Click any day for a popover with everything due that day.
Sync
Realtime sync is enabled by default. If you are offline, entries are queued and synced automatically when you are back online.
Notifications
Local reminders cover due dates, quick note saves, and study timer endings. Subscription renewal alerts can be set for 1, 3, or 5 days before renewal.
Summary & Images Pro
Pro unlocks the Summary dashboard, the Images category, animated backgrounds, and a higher entry limit for heavier use.
API Access Pro+
Third Arm does not include a built-in AI assistant. Pro+ adds optional AI Connect prompt export and read-only API tokens for your own external AI tools.
Choose your plan
Start free. Upgrade when you need more. Study timers are unlimited on every plan. See Terms of Use / EULA and Privacy Policy.
Free
50 entries
- Quick Notes, Diary, Reminders, Habits, Links
- Subscriptions, Payments, Flash Cards
- Calendar view
- Sync across devices
- Menu bar quick-add
- Study Timers (unlimited)
If you have ever subscribed before, you keep up to 120 entries after expiry.
Pro
500 entries
- Everything in Free
- Summary dashboard
- Images category
- Animated backgrounds
- Permanent 120 entries after cancelling
Pro+
2,000 entries
- Everything in Pro
- Optional AI Connect prompt export
- Read-only API tokens for your own AI workflows
- Best for advanced automation and research-heavy setups
Start using Third Arm in minutes
Download, sign in, and start capturing. Your data syncs automatically, and the layout stays focused on fast access.
Download & sign in
Get Third Arm from the Mac App Store. Sign in with Email, Apple, or Google.
Capture from the menu bar
Save reminders, habits, links, timers, subscriptions, diary entries, flash cards, payments, or quick notes without opening the full window.
Organize across categories
Use the sidebar to jump between Diary, Quick Notes, Reminders, Habits, Links, Subscriptions, Payments, Study Timers, Flash Cards, Images, and Settings.
Upgrade when you need more
Pro unlocks Summary, Images, and appearance upgrades. Pro+ adds higher limits and optional API access for your own AI tools.