Two ways to the taxable benefit
The 1% rule is convenient: list price times 1%, plus 0.03% per kilometre of distance, done. But it is a flat rate and therefore often inaccurate. The logbook under § 8(2) sentence 4 EStG is the alternative. Here only the part of the actual costs attributable to your private trips and the commute is taxed.
How the logbook method calculates
First, the car's total costs for one year are determined: energy, insurance, vehicle tax, servicing, repairs and depreciation or the leasing instalment, each including VAT. Then the share of private kilometres and commute kilometres in total mileage is determined. This share of the costs is the taxable benefit.
An example with the default values of our company car calculator: running costs of €4,500 and depreciation of €7,500 a year, €12,000 in total. You drive 25,000 km a year, 5,000 km of them privately. The 20 km commute on 15 days a month adds up to 7,200 km. Private and commute trips account for 12,200 km, i.e. 48.8%. The taxable benefit is €12,000 × 48.8% ÷ 12 = €488 a month, instead of €720 under the 1% rule. At €5,000 gross and tax class I you save about €115 net a month.
For electric cars and qualifying hybrids, depreciation or the leasing instalment is only counted at a quarter or a half under the logbook method too. This lowers the benefit further.
When the logbook pays off
- You drive a lot for business and little privately.
- The car has a high list price but low actual costs, for example because it was bought used or is already depreciated.
- You have a long commute that you rarely drive.
- The car is hardly used for holiday trips.
Conversely, the flat rate is cheaper if you drive a lot privately or the car is expensive to run. Note that you often only know the actual costs at the end of the year. Many employers therefore apply provisional figures during the year and correct them later.
What the tax office requires
A logbook is only accepted if it is kept promptly, completely and in closed form. For each business trip it must record the date, mileage at start and end, destination, purpose and business partners visited. For private trips the mileage is enough; for the commute a short note.
Later changes must be visible. A spreadsheet that can be overwritten at any time does not meet this requirement. Electronic logbooks are permitted if they log changes. Minor flaws do not automatically lead to rejection, but serious gaps do. The 1% rule then applies retroactively.
Also plan for the receipts: the logbook method only counts costs that were actually incurred and documented. Fuel receipts, workshop invoices, insurance and tax notices and the depreciation schedule or leasing contract all belong here. If your employer does the bookkeeping, it should tell you the annual costs. Without this figure the taxable benefit cannot be calculated, and even a perfectly kept logbook is of no use.
Switching methods
The method must be applied consistently to one vehicle for a calendar year. A switch during the year is only possible when the vehicle changes. In your income tax return, however, you can depart from the payroll treatment and prove the logbook for the entire year.
Conclusion
The logbook can pay off but takes discipline. Work through your kilometres and costs before you commit. The company car calculator shows the difference to the 1% rule directly.