DriveHub

Fahrtenbuch or the 1% rule — and why a half-kept logbook is worse than none

The choice, and where it is actually decided

If a car is available to you privately, German tax law values that benefit one of two ways. Either the flat 1% of the list price per month (plus 0.03% per kilometre of commute), or the actual cost apportioned by business use — and the second is allowed only where "ein ordnungsgemäßes Fahrtenbuch" exists (§ 6 Abs. 1 Nr. 4 Satz 3 EStG).

Most articles stop at the arithmetic: an expensive car driven mostly for business, and the logbook wins by a wide margin. That part is easy. The part that decides real cases is whether the logbook is ordnungsgemäß, and that is defined not in the statute but in R 8.1 Abs. 9 Nr. 2 LStR.

What has to be in it

Per business trip, in the guideline's own words: "Datum und Kilometerstand zu Beginn und Ende jeder einzelnen beruflich veranlassten Fahrt, Reiseziel, Reisezweck und aufgesuchte Geschäftspartner."

• Date
• odometer at start and end
• destination
• purpose
• the business partner you visited

Private trips need only "Kilometerangaben". The commute home↔first workplace needs "jeweils ein kurzer Vermerk". Detours must be recorded.

The form requirement is what fails, not the fields

Three things trip people up, and none of them is a missing column.

• The closed chain. The book must be kept "zeitnah und in geschlossener Form", and the entries must reproduce the trips "vollständig und in ihrem fortlaufenden Zusammenhang" including the total odometer at the end of each. One unbroken sequence — private driving included. Not a list of business trips with the rest left out.
• Electronic books must be tamper-evident. Later changes must be technically excluded, or at minimum documented — and documented in the exported file, so the record stands on its own without asking whoever administers the system.
• The seven-day rule. FG Niedersachsen, 23 January 2019 – 3 K 107/18, accepts automatic capture where the driver enters the trip purpose within seven calendar days. That is the window in which an automatic system stays compliant, and it is short.

There is one piece of relief worth knowing: BFH, 10 April 2008 – VI R 38/06 holds that minor deficiencies alone do not invalidate a logbook.

What it costs to get it wrong

The tax office reverts to the 1% / 0.03% method, which is usually far more expensive than the outcome you were aiming at. And the failure is not per trip: a break in the chain invalidates the logbook for the entire year.

That is the reason a half-kept logbook is the worst of the three options. Keeping none costs you the 1% valuation you would have had anyway. Keeping one with a gap in August costs you the same 1% valuation and the year of effort.

Why an app rather than a notebook

Nothing above requires software; a paper book with the same fields is compliant, and courts say so. What software changes is the failure mode — and in Germany the failure mode is precisely a gap, which is a thing that happens to people who are busy rather than to people who are careless.

DriveHub records every drive in the background, business and private alike, which is what a closed chain means. The seven-day window then applies to one thing only: telling it which trips were business, and why.

Two fields it does not yet carry, stated plainly because a page that hid them would be useless to you: the per-trip odometer reading, and the business partner visited as a field of its own.

This page quotes the guideline and the two decisions by name so you can read them. It is not tax advice and does not know your situation. Where the money matters, ask your Steuerberater — and bring the records.