Guide
Tachograph calibration rules: the 2 year and 6 year intervals
Updated
The intervals are short, specific and easy to check on the plaque. These are the rules as gov.uk states them for goods vehicle operators.
Who may do the work
DVSA guidance states that all tachographs used for recording drivers' hours, whether analogue, digital or smart, must be properly installed, calibrated and sealed, and that this task must be performed either by a vehicle manufacturer or an approved tachograph calibration centre. An installation plaque must be fixed to or near the tachograph, and centres issue a certificate showing details of any inspection conducted (gov.uk).
The intervals
| Tachograph type | What is required |
|---|---|
| Analogue | Inspected every 2 years and recalibrated every 6 years |
| Digital | Recalibrated every 2 years, plus on the trigger events below |
| Smart 1 and smart 2 | Recalibrated every 2 years, plus on the trigger events below |
The events that trigger a recalibration early
For digital and smart tachographs, gov.uk lists recalibration as required every 2 years, after any repair, if the vehicle registration number changes, if UTC is out by more than 20 minutes, and after an alteration to the circumference of the tyres or characteristic coefficient. Inspection and recalibration dates are shown on the plaque and updated by calibration centres, and operators must ensure the requirements are complied with before a new or used vehicle goes into service.
The tyre trigger catches operators out more than any other. A change of tyre size, not just a change of tyre, alters the characteristic coefficient and means the unit needs recalibrating.
If the tachograph breaks
- gov.uk states that in the event of a breakdown or faulty operation the tachograph must be repaired as soon as possible, and if the vehicle cannot return to base within a week the repair must be carried out en route.
- For faults involving digital or smart tachographs, operators should ask the repair centre to download any data held on the unit. Where that is not possible the centre should issue a certificate of undownloadability, which must be kept for at least 12 months.
- A repair triggers a recalibration, so budget the two together rather than treating the repair as the end of the job.
Which unit has to be fitted
gov.uk sets out the smart 2 fitting dates: a full or transitional smart 2 tachograph must be fitted on or after 21 February 2024 into all newly registered in-scope vehicles regardless of journey type; from 24 December 2025 all newly registered goods vehicles must have a full smart 2 tachograph; and on or after 1 July 2026 a full smart 2 tachograph must be fitted into goods vehicles over 2.5 tonnes used for international journeys for hire and reward. Goods vehicles over 2.5 tonnes and under 3.5 tonnes used only in the UK do not have to have a tachograph fitted (gov.uk). Rules change: check the guidance for your own operation before acting on any summary, including this one.