Principal Task vs To Do Machine
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Principal Task
This app helps you manage tasks by tracking your completion rate against new tasks created. It offers a unique 'Task Velocity' score to show if you're keeping up with your workload. Organize with folders, contexts, and priorities, with advanced features available through a premium subscription.
- Task Velocity score
- GTD-native structure
- Due dates and repeating tasks
- Markdown support
- Kanban boards
- Private templates
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Track your Task Velocity — the ratio of tasks you complete against the ones you create, updated every day. See at a glance whether you're ahead or falling behind, not just what's on your list. Principal Task is a GTD-native task manager built for people who've outgrown to-do apps. Folders, contexts, priorities, statuses, and unlimited nested subtasks — organized the way real work actually happens. TASK VELOCITY Your 30-day completed-vs-created ratio, shown as a simple multiplier. Free members see their current score. Premium unlocks the full history, filterable by folder, context, priority, and status. SYSTEM HEALTH A live verdict — Healthy, Strained, or Overloaded — so you know where things stand today, separate from where they're heading. BUILT FOR GTD Folders and sub-folders, contexts, priorities, statuses, and stars. Subtasks nest as deep as you need, with independent completion — no forced parent-child status. KANBAN, HEATMAP, TEMPLATES See your work as a board. Watch your activity over time. Turn repeatable processes into templates you can apply in one tap. BUILT FOR AI ASSISTANTS Principal Task connects to AI assistants over MCP — read and write your tasks, subtasks, and folders directly from the assistant you already use. SHARE WITHOUT FRICTION Share a task list with a four-word link. No account required to view. You control how long it stays open. Free, no credit card. Premium is about $3/month or $24/year, and it doesn't limit how much you can do — it unlocks Task Velocity history, Kanban, the Activity Heatmap, and private templates. Principal Task. Software that gets out of the way. Terms of Use: https://principaltask.com/terms
To Do Machine
This productivity app allows users to fully customize their to-do list and workflow using natural language commands. It offers AI-powered task creation, project management, and calendar integration, syncing seamlessly across Mac and iOS devices.
- Natural language interface for customization
- AI-powered task creation and triage
- Multiple project views (list, kanban, calendar)
- Customizable statuses, fields, and automations
- Two-way calendar sync (Apple/Google)
- Real-time sync across Mac and iOS
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The only productivity app you design yourself. Most to-do apps make you bend to their rules. To Do Machine flips the workshop on its head — open the back panel, swap the parts, paint it your color. Talk to it in plain English and watch your task inbox, your projects, and your entire workflow rebuild themselves in real time. Built natively for Mac and iOS. Perfectly in sync. — WHO IT'S FOR — For the people who've tried every to-do app and bounced off them all. For the ones who keep building systems in Notion, then abandoning them. For anyone whose brain works a specific way and is tired of apps that don't. To Do Machine isn't another opinionated workflow. It's a workshop where you build the one that fits you. — DESIGN IT YOURSELF — Tell To Do Machine what you want and it remakes the app around you. "Make the inbox darker and put due dates on the right" — done. Switch any project to list, kanban, calendar, focus, or blueprint view. Invent your own statuses, fields, and automations, project by project. Every tweak syncs to all your devices instantly. — AI THAT DOES THE TYPING — Just say what's on your mind. To Do Machine writes the tasks, breaks them into projects, sets reminders, and finds time on your calendar — no tapping the + button. "Plan my Q3" → full project with milestones, weekly check-ins, and time blocks. Auto-triage your inbox: priority, due dates, parent project. A daily standup that drafts your day before you've finished your coffee. — CALENDAR IN, DAY OUT — Connect Apple or Google Calendar and your tasks thread themselves between your meetings. Two-way sync with Apple or Google Calendar. Time-blocking that respects your meetings, focus blocks, and breaks. Move a meeting and your tasks move with it. — INSTANTLY SYNCED BETWEEN iOS AND MAC — Tasks, projects, and calendars sync in milliseconds. Custom layouts and themes travel with you. Redesign your inbox on Mac at lunch — it's waiting on your iPhone by the time you stand up. Assembled in Brooklyn, NY. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is in-app purchases: To Do Machine at none against Principal Task's 2. To Do Machine also leads on update cadence (every 2 weeks vs every 3 months) and ratings volume (8 vs 1). Principal Task's advantage is iOS requirement (15.0 vs 17.6). On price, rating, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Principal Task sells 2 in-app purchases, starting at $3.99 per month. To Do Machine asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for Principal Task against 5.0 for To Do Machine. That said, the two scores are not equally well evidenced: To Do Machine has 8 ratings behind it against 1, so its average is the more settled of the two.
Principal Task ships an update every 3 months, To Do Machine every 2 weeks. The most recent releases landed on October 1, 2026 and October 2, 2026 respectively.
| Parameter | Principal Task | To Do Machine |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) | 5.0 (8 ratings) |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 1 | 8 — better |
| Update frequency | Every 3 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod — better | iPhone, Mac |
| Requires iOS | 15.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 32 MB | 30 MB |
| Age rating | 4+ | 17+ |
| Developer | Zechariah Schwenk | Electric Lantern LLC |
Customer experience
Principal Task
To Do Machine
In-app purchases
Principal Task
- Monthly Subscription$3.991 Month
- Annual Subscription$29.991 Year
To Do Machine
No in-app purchases









