Estimate your THC level. Transparent. Local. Private.
A multi-compartment model with an openly documented methodology. Runs entirely on your device. No account, no tracking.
Adults 18+ only. Not medical advice. No statement about driving ability.
Everything you need to understand
Eight thoughtful building blocks — transparently documented, private by design.
Cockpit Chart
History of your estimated plasma concentration plus forecast in two scenarios: typical and conservative.
Widget & Live Activity
Current estimate on the lock screen, inside the Dynamic Island and in an Apple-Watch-ready look.
Reverse Lookup
Ask in reverse: when should you stop consuming to be below threshold Y by time X?
Deep Insights
84-day calendar, weekday trends and pattern analysis — understand your consumption instead of just counting it.
Siri Shortcut
"Log cannabis consumption" by voice. Native App Intents, no detours, no shell.
Liquid Glass UI
Fully built for iOS 26: fluid, dynamic surfaces that react to content and light.
Privacy by Design
All data stored locally in SwiftData. No server, no account, no tracking, no AdMob.
Local Backup
JSON export of your data — fully portable, fully yours. Restore with a single tap.
Methodology you can verify
The model is based on a multi-compartment pharmacokinetic approach for THC as described in the published literature (Heuberger et al., Huestis, Sharma et al. and others). Inhalation and oral routes are parametrised separately. Results are estimates with substantial individual variability — they do not replace lab diagnostics and make no statement about driving fitness, criminal law or medical questions. The full source list with DOIs is visible inside the app on the Methodology screen.
Frequently asked questions
Is THC Monitor a medical device?
No. THC Monitor is an estimation tool — not a medical device and not a forensic measurement. It does not make any statement about driving fitness, criminal liability or medical diagnosis. For medical questions, consult a physician.
Is any of my data uploaded?
No. All consumption data lives exclusively on your iPhone inside SwiftData. There is no account, no server, no tracking and no analytics. Backups are JSON files exported locally via the iOS share sheet.
How much does the app cost?
There is a free tier covering the core features. THC Monitor Pro costs €3.99 per month or €24.99 per year and unlocks the cockpit chart, reverse lookup, deep insights, widgets, live activity and Siri shortcuts. Pro starts with a 7-day trial.
Does the app work outside Germany?
Yes. The app is region-aware for Germany, Austria and Switzerland. Cannabis laws differ by country (KCanG in Germany, SMG in Austria, BetmG in Switzerland). Inform yourself about the legal situation where you live.
How accurate is the model?
The model returns an estimate with substantial individual variability — metabolism, body fat, tolerance and product potency vary widely. Never rely on a single value for legal or medical decisions. The sources are visible inside the app on the Methodology screen.
I'm an existing user of the old app — will my data be lost?
No. Existing consumption data and your Pro status are migrated automatically when you update to the native iOS version — Pro via StoreKit sync with your Apple ID, consumption logs via the local migrator.