OpenFahrtenbuchPhone GPS
One tap to start, one tap to stop. Recording keeps running in the background while the trip is active. Start and destination addresses are filled in automatically.
No extra hardware
Open source · iPhone and Android
Free mileage log.With or without an OBD plug.
Record trips by GPS, read the real odometer through a cheap Bluetooth adapter, or simply type them in. Built to the German tax office rules, with no subscription and no account.
- 0 euros, no subscription
- No account
- Data stays on your phone
- MIT license
How it works
Three ways to record a trip.
You decide how much hardware you want. All three end up in the same gap-free logbook.
OBD adapter, optional
A cheap Bluetooth LE adapter (ELM327) reads the real odometer from the car when the vehicle provides it, otherwise the speed. Trips can start and stop automatically.
Buy once, no subscriptionBy hand
Read the odometer, enter destination and purpose, done. Suggestions from previous trips and saved places save typing.
Always worksThen: classify the trip.
Saved places such as home, office or customers fill in destination, purpose and business partner automatically. Anything still missing is shown before the deadline runs out.
BusinessDestination, purpose, business partner, route for detours
PrivateKilometers are enough, the destination can be hidden in the export
CommuteA short note is enough
Tax office
Built to the rules the Finanzamt applies.
A logbook only counts if it is kept properly. What that means is set out in R 8.1 (9) LStR, the BMF circular on private use of company cars and German case law. This is how OpenFahrtenbuch meets each requirement.
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Timely
R 8.1 (9) no. 2 LStRTrips are created live while you drive. Incomplete trips show a deadline, and the app reminds you to complete them within 7 days.
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Closed form
R 8.1 (9) no. 2 LStRAll trips are numbered consecutively in one logbook per vehicle. Deleting is impossible. A wrong trip is voided with a reason and stays visible.
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Complete and gap-free
R 8.1 (9) no. 2 LStREach trip starts at the odometer reading where the last one ended. The app flags odometer gaps and overlaps right away.
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Required details for business trips
R 8.1 (9) no. 2 LStR, BMF circularDate, odometer at start and end, destination, purpose and business partner are required fields. There is a route field for detours. Only then is the trip complete.
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No silent changes
BMF circular, FG Düsseldorf 3 K 1887/22 H(L), BFH VI B 37/23Every entry and every change goes into an append-only SHA-256 hash chain. Changes appear in the PDF right next to the trip, with date, time and the original value. 7 days after the trip it is locked.
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Printable and machine-readable
§ 147 AOA4 PDF for the tax office and your tax advisor, CSV for machine evaluation, and an integrity check in the app that recomputes the whole chain.
To be clear: the German tax office does not certify any logbook software, paid or free. Whether a logbook is accepted always depends on how it is kept. OpenFahrtenbuch is built to the published requirements. This is not tax advice; if in doubt, ask your tax advisor.
Compare
What a mileage log should cost: nothing.
Subscription logbooks with an OBD plug are convenient, but expensive. OpenFahrtenbuch does the core job for free.
| Feature | OpenFahrtenbuch | Typical plug-in logbook subscription |
|---|---|---|
| Price | 0 euros | about 22–25 euros per month |
| Contract | None | Subscription, often with a minimum term |
| Hardware | None needed. Optionally a standard BLE adapter, bought once | The provider’s plug |
| Recording | GPS, OBD adapter or manual | Through the plug |
| Account | Not needed | Required |
| Where your trips live | On your phone | On the provider’s servers |
| Source code | Open, MIT license | Closed |
| Tamper protection | Hash chain, verifiable in the app | Vendor claim |
| Web portal and fleet management | No, one app per phone | Usually yes |
Subscription logbook figures: typical market values as of October 2026. Individual providers and plans differ.
Your logbook belongs to you.
Where you drive is nobody’s business. That is why there is no server the app sends anything to. Everything stays on your phone until you share an export yourself.
- No account, no serverWe never see your trips.
- No tracking, no adsNo analytics or advertising SDKs in the app.
- GPS only during a tripNo background location when nothing is recording.
- Hide private destinationsOn request, private trips show only kilometers in the export.
Also included
Everything a logbook needs day to day.
Multiple vehicles and drivers
Each vehicle has its own gap-free logbook. Who drove is recorded with the trip.
Saved places
Home, office and customers are recognized at the destination and fill in purpose and business partner.
Costs and the 1% rule
Log fuel, service and insurance and see whether the logbook or the 1% rule is cheaper for you.
Export
PDF for the tax office and your advisor, CSV for spreadsheets and audit software, JSON as a full backup.
Backup and restore
The JSON backup contains all your data and can be restored on a new phone.
German and English
The app is available in both languages.
Questions
Frequently asked questions
Will the tax office accept it?
No tax office certifies software. OpenFahrtenbuch implements the published requirements: timely, complete, closed form, required details for business trips and documented changes. What matters in the end is that you keep the logbook carefully.
Do I need an OBD adapter?
No. GPS and manual entry work without any hardware. An adapter is worth it if you don’t want to read the odometer yourself and want trips to start automatically. Bluetooth LE adapters with the ELM327 protocol work, for example vLinker MC+ or FS BLE, OBDLink CX or Veepeak BLE+.
What does it really cost?
Nothing. No subscription, no ads, no in-app purchases. The source code is on GitHub under the MIT license.
What happens after 7 days?
Complete trips are locked 7 days after the trip and can no longer be changed. Until then you can correct them; every change is documented with date, time and the original value.
What if I lose my phone?
Because there is no server, there is no cloud copy on our side either. Create a JSON backup regularly and keep it wherever you like, such as your own cloud storage or your computer.
Keep a mileage log without paying for it.
Free for iPhone and Android. Made by Codext GmbH in Wolpertshausen, Germany.