Buchhaltung & LogistikJuly 22, 2026·5 min read

Electronic mileage log vs. Excel: What the German tax office accepts

Excel mileage logs regularly fail tax audits. What the case law of the Federal Fiscal Court and the GoBD require — and what matters in electronic solutions.

The point of contention: the closed form

A mileage log only protects you from flat-rate taxation under the 1% rule if the tax office recognizes it as proper. The case law of the Federal Fiscal Court (Bundesfinanzhof, BFH) requires prompt record-keeping in a closed form: the records must be such that retroactive insertions or changes are impossible, or at least remain clearly recognizable as such. This is exactly where spreadsheets fail.

Why Excel fails

The BFH already ruled in its judgment of November 16, 2005 (VI R 64/04) that records created with spreadsheet programs such as Excel are not a proper mileage log: entries can be changed at any time without a trace, so the closed form is missing. A subsequent printout changes nothing. If the mileage log is rejected, the 1% rule of § 6 para. 1 no. 4 EStG (German Income Tax Act) applies retroactively — for the entire audit period, frequently with five-figure back payments plus interest per vehicle.

What an electronic mileage log must deliver

Immutability: changes must be technically impossible or fully logged and visible — a core criterion of the GoBD
Prompt recording: trips must be recorded immediately or within a few days; catching up weeks later from calendars does not count as prompt
Complete mandatory details per trip: date, odometer readings at the start and end, destination, purpose of the trip, and the business partner visited
Traceability and retention: machine-readable evaluability and retention of the data under § 147 AO (German Fiscal Code) for the statutory period
Retroactive purpose changes (e.g., from "private" to "business") only with a documented change log

GPS solutions are no sure thing

Even a telematics mileage log is not automatically tax-office-proof: while the technology records routes and odometer readings tamper-proof, the purpose of the trip and the business partner must still be added manually and promptly. Anyone who postpones this post-processing for months risks rejection despite GPS recording. Also make sure the provider offers a GoBD-compliant change log and a data export for tax audits.

Mileage log or 1% rule: a matter of arithmetic

Whether the effort pays off depends on the gross list price and the private-use share: the more expensive the vehicle and the lower the private use, the more the numbers favor the mileage log. A decision aid with worked examples is offered by the comparison Mileage log or 1% rule; the requirements for an audit-proof implementation in detail are shown by the GoBD Mileage Log.

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Frequently asked questions

Is a handwritten notebook sufficient as a mileage log?

Yes, a bound book with consecutive, prompt, and complete entries satisfies the closed-form requirement and is recognized. The downsides are the recording effort, the lack of evaluability, and the risk of loss. Loose sheets, sticky notes, or lists compiled after the fact, by contrast, are not sufficient.

Can I "lock down" my Excel mileage log by printing it out?

No. What matters is the form of the ongoing record: since Excel files can be changed arbitrarily and without a trace until printed, the closed form is missing from the outset. The BFH has ruled on this expressly. Even a monthly printout with a signature does not cure this defect.

What happens with minor errors in the mileage log?

According to the case law, isolated minor defects do not necessarily lead to rejection if the entries are plausible and complete overall. Systematic gaps, rounded odometer readings, missing business partners, or contradictions with workshop invoices and fuel receipts, by contrast, regularly lead to rejection of the entire mileage log.

For which vehicles do I have to keep a mileage log at all?

There is no obligation — the mileage log is an alternative to the 1% rule for valuing the private use of company vehicles. It pays off above all with a low private-use share, a high gross list price, or vehicles that are already fully depreciated. The method must be chosen uniformly per vehicle for the entire fiscal year.

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