Tachograph Calibration Rules: A Checklist for HGV Operators
Know when digital, smart and analogue tachographs need inspection or recalibration, what triggers an early visit and which evidence to retain.
A digital or smart tachograph is not safely controlled by adding two years to the last workshop invoice. Operators must check the calibration plaque and certificate, monitor changes that trigger earlier recalibration and ensure the requirement is met before a new or used vehicle enters service.
This guide concerns vehicles required to use tachographs. Exemptions and the applicable drivers’ hours regime should be established separately.
The basic calibration intervals
DVSA guidance states that all analogue, digital and smart tachographs used to record drivers’ hours must be properly installed, calibrated and sealed by a vehicle manufacturer or approved tachograph calibration centre.
Digital and smart tachographs must be recalibrated every two years. Analogue tachographs must be inspected every two years and recalibrated every six years. The installation or calibration plaque shows relevant dates, and the centre provides a certificate for the inspection.
Treat the plaque, certificate and fleet planner as three controls that should agree. A planner date copied incorrectly from an invoice should not override the equipment evidence.
Events that trigger earlier recalibration
For digital and smart tachographs, do not wait for the two-year date after:
- a repair to the tachograph;
- a change of vehicle registration number;
- UTC being wrong by more than 20 minutes;
- an alteration to tyre circumference or the vehicle’s characteristic coefficient.
Tyre and drivetrain work can therefore affect tachograph control even when the scheduled calibration is months away. Build a workshop question into tyre-size, gearbox and relevant vehicle-modification jobs: “Does this change require tachograph recalibration?” Escalate the answer to the competent workshop or approved centre.
First-use checks for new and used vehicles
Before a vehicle begins work, verify the tachograph type is permitted for the operation, the plaque relates to the vehicle, the calibration is in date, seals appear intact and the certificate is available. Check the registration and relevant vehicle details rather than assuming the seller’s file belongs to the unit.
The current HGV inspection manual treats missing, mismatched or invalid calibration evidence as a test issue for vehicles required to be fitted. An annual test is not a substitute for the operator’s first-use control.
A practical planner record
For each vehicle record:
| Field | Why it matters |
|---|---|
| Tachograph type | Confirms the applicable equipment and replacement rules |
| Centre and certificate reference | Supports traceability |
| Calibration/inspection date | Establishes the last verified event |
| Next scheduled date | Creates a forward warning |
| Plaque checked by/date | Confirms the physical vehicle agrees with the office record |
| Early-trigger review | Records repairs, VRM, time and tyre changes |
Set warnings early enough to book an approved centre without taking the vehicle out of service unexpectedly. HauliK can track a tachograph calibration date within the fleet record, but it does not inspect, calibrate or analyse tachographs.
Faults, breakdowns and seals
DVSA says a tachograph fault must be repaired as soon as possible. If the vehicle cannot return to base within a week, repair must be carried out en route under the applicable rules. Drivers need the correct manual records while equipment is faulty; this is not permission to continue indefinitely.
Ask the repair centre to download data held in a faulty digital or smart unit. If it cannot be downloaded, the centre should issue a certificate of undownloadability, which DVSA says must be retained for at least 12 months.
A broken seal also needs immediate attention. Record when and how it was discovered, protect the relevant manual evidence and obtain competent instructions. Do not reseal or alter equipment informally.
Monthly control check
Once a month, reconcile the fleet list to the calibration planner. Check vehicles joining or leaving, recent repairs, registration changes, tyre specification changes, clock discrepancies and missing certificates. Sample the plaque on a vehicle rather than reviewing only office dates.
Make responsibility explicit between transport, workshop and finance. The invoice payer may see the calibration bill first, but the transport manager needs the certificate and next date.
Common mistakes
- treating two years as the only trigger;
- recording a date without the certificate or plaque check;
- missing a VRM change after cherished-number or fleet changes;
- changing tyre circumference without a tachograph review;
- assuming the annual test will manage calibration;
- failing to retrieve data when a unit is replaced;
- using a non-approved provider for regulated work.
Frequently asked questions
How often is a digital tachograph calibrated?
Every two years, and earlier after the specific events listed by DVSA, including repair, VRM change, excessive UTC error and relevant tyre-circumference or characteristic-coefficient alteration.
Can my usual workshop calibrate it?
Only if it is an approved tachograph calibration centre or the work is performed by an authorised vehicle manufacturer within the rules. Use the official centre finder.
Does HauliK download or analyse tachograph data?
No. HauliK can help track dates and organise fleet records, but tachograph download, calibration and analysis require the appropriate specialist systems and providers.
What should be kept after a fault?
Keep repair and calibration evidence, the manual records required during the fault, downloaded data where available, and any certificate of undownloadability issued by the centre.
Sources & further reading
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