Guide
The mileage log: what goes in it and why it is worth keeping
For tax purposes the mileage log is the basis both for the mileage allowance and for the use of a company car. Without it, all that is left is an estimate, and an estimate is always a worse starting point than a record.
Updated 21.9.2026. This guide is general information, not legal advice — check the regulations in force from the authority's own guidance.
What the mileage log is needed for
When an employee uses their own car for business driving, the mileage allowance is paid on the kilometres driven, and those must be demonstrable. With a company car, the log separates business and private driving, which affects the taxable value. In both cases missing records turn into a loss for the company in taxation.
What an entry contains
For every drive you record the time, the departure and destination — that is, the route — the odometer reading at the start and at the end, the kilometres driven, the purpose of the trip and who used the car. For private driving the number of kilometres is enough. The entry must be made during the drive or immediately after it, not a month later from memory.
Odometer readings, not estimates
When the kilometres are calculated from odometer readings they can be verified. An estimated figure is exactly what an inspection seizes on. The reading at the start and at the end is also the fastest way to record: two numbers, no recollecting the route.
Business and private driving separately
Mixed-up trips are a problem both for mileage allowances and for the taxable value of a company car. When private driving is marked with its own choice at the moment of entry, the separation is done and does not have to be unpicked later.
Retention
The mileage log is part of the accounting voucher material and must be retained. In electronic form it does not vanish into the glove box or fade, and it can be retrieved years later.
FAQ
Is an electronic mileage log acceptable?
Yes. The Tax Administration does not require paper, only that the required details have been recorded reliably and can be produced.
Does the route of a private trip have to be recorded?
For private driving the number of kilometres is usually enough; for business driving the route and the purpose are recorded.
What if there is no mileage log at all?
In that case the tax authority may estimate the share of private use, and the estimate is typically unfavourable to the taxpayer.
How Kirjus helps here
In Kirjus a drive is recorded from odometer readings: the kilometres are calculated automatically, the route and purpose are written once, and private driving is marked with a single choice. A drive can be allocated to a site, so the trips also show up in that site's costs.
Read also
Vehicles and the mileage log
Inspection and insurance dates with reminders, a mileage log with the kilometres, and the separation of business and private driving for the tax authority.
Daily allowances and mileage
Full and partial daily allowances, the meal allowance and mileage allowances with trailer and passenger supplements, according to the Tax Administration's current values.