Tachograph vs. mileage log – what are the differences
A tachograph and a mileage log are often confused, even though each serves a different purpose and rests on a different piece of law. We explain the differences and advise when you need both.
Two systems, two different purposes
A tachograph is a recording device prescribed by European legislation. Its role is to record driving times, breaks and rest periods so that compliance with social rules in road transport can be checked.
A mileage log, by contrast, is an accounting and tax document. It proves that the vehicle was used for business and serves as supporting evidence when claiming vehicle costs. These are therefore two separate worlds – one policed by transport rules, the other by tax rules.
A different legal basis
The tachograph rests on Regulations (EC) No 561/2006 and (EU) No 165/2014, which apply directly across the whole European Union. The obligation is tied to the type and mass of the vehicle and to the nature of the transport.
The mileage log rests on national tax legislation. Since 1 January 2026 the content is prescribed by § 85n of the Slovak VAT Act for M1, L1e and L3e vehicles; beyond those there is no single officially prescribed form, but it must contain the data from which every journey can be unambiguously reconstructed – date, route, purpose, distance and odometer reading.
That is precisely why the rules for a mileage log can differ from state to state, while the tachograph rules are harmonised across the EU.
What each of them records
The tachograph records the driver's activity over time: driving, other work, availability and rest. The data is tied to the driver card and at a roadside check is examined for the day of the check and the preceding 56 days.
The mileage log records individual vehicle journeys: from where to where, for what purpose, how many kilometres and at what odometer reading. It is interested in the vehicle and the purpose of the journey, not in whether the driver had enough rest.
A full mileage log therefore cannot simply be produced from tachograph data – it lacks the purpose of the journey as well as the distinction between private and business trips.
Neither replaces the other
This is the key point: a tachograph does not replace a mileage log and a mileage log does not replace a tachograph. A company operating vehicles that fall under Regulation 561/2006 generally needs both – the tachograph for transport rules and the mileage log for tax.
Equally, GPS tracking does not replace a tachograph either. A GPS unit is not an approved recording device within the meaning of Regulation 165/2014 and its data does not carry the same standing when driving times are checked.
When you need which
If you drive a car or a van exclusively within one country and the vehicle does not fall under the limits of the regulation, you do not need a tachograph – but you do need a mileage log if you are claiming vehicle costs.
If you operate vehicles over 3.5 tonnes, or from 1 July 2026 drive internationally with a vehicle over 2.5 tonnes, you need a tachograph and at the same time need to keep a mileage log for tax purposes.
In both cases it is better to seek advice on borderline situations – transport obligations with a transport adviser, tax matters with an accountant.
How to simplify this in practice
While the tachograph works on its own and its data is downloaded at prescribed intervals, most companies still keep the mileage log by hand – and that is exactly where most of the errors and lost hours arise.
An automatic mileage log from GPS removes that problem: routes, times and distances record themselves, journeys are separated into business and private, and the finished report is exported to PDF or XLS for the accountant. It will not replace the tachograph, but it will replace the paperwork around the mileage log.
FAQ
Does a tachograph replace a mileage log?
No. A tachograph records driving and rest times under transport rules; a mileage log proves the vehicle was used for business for tax purposes. They are two different documents.
Can I produce a mileage log from tachograph data?
Not a complete one. The tachograph lacks the purpose of the journey and the distinction between business and private trips, both of which the mileage log needs.
Does GPS tracking replace a tachograph?
No. A GPS unit is not an approved recording device under Regulation (EU) No 165/2014. GPS handles the mileage log, position and costs, not the statutory record of driving times.
Do I need both at once?
If your vehicles fall under Regulation 561/2006, generally yes – the tachograph for transport rules and the mileage log for claiming costs.
What is the difference in legal basis?
The tachograph rests on European Regulations 561/2006 and 165/2014, which apply across the whole EU. The mileage log rests on national tax legislation and therefore differs from state to state.
Leave the tachograph to the rules and the mileage log to us. SaveTrack fills it in automatically from GPS – from €6 a month with no lock-in. Write to info@savetrack.sk or call +421 908 918 880.
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