Calculate your estimated driving time remaining
Enter driving time—not total shift time—from the previous and current fixed weeks. Use decimal hours, for example 37.5 for 37 hours 30 minutes.
Important: This is an educational estimate, not a compliance decision. Daily driving limits, breaks, rest, working-time rules, exemptions, employer instructions and the authoritative tachograph record still apply.
How does the 90-hour rule work?
The calculation always looks at two neighbouring fixed weeks. Add the driving time in the previous fixed week to the driving time in the current fixed week. The combined total must not exceed 90 hours.
The pairs overlap: check week one plus week two, then week two plus week three, then week three plus week four. The calculation does not reset after every second Sunday.
A simple 90-hour-rule example
If week two contains 38 hours, week three is checked against week two—not week one. Under the two-week total alone, week three could contain up to 52 hours because 38 + 52 = 90. The separate 56-hour weekly maximum also applies.
How is HGV driving time remaining calculated?
- Weekly allowance remaining: 56 hours minus driving recorded in the current fixed week.
- Two-week allowance remaining: 90 hours minus the previous and current fixed-week driving totals.
The calculator uses the smaller result. That figure is not unconditional permission to drive: daily limits, breaks, daily and weekly rest, working-time limits and applicable derogations must still be considered.
What counts towards the 90 hours?
The rule concerns driving time, not the whole paid shift. Other work, breaks and periods of availability do not become driving time simply because they occur during the duty. Use the tachograph record as the authoritative source for driving totals.
How do the nine-hour and ten-hour daily limits fit in?
The normal daily driving limit is nine hours. It may be extended to ten hours no more than twice in a fixed week. These limits apply alongside the 56-hour weekly and 90-hour two-week limits.
HGV 90-hour rule questions
Does the 90-hour limit reset every fortnight?
No. It applies to every pair of consecutive fixed weeks, so the calculation overlaps from one week to the next.
Can an HGV driver drive 56 hours in both weeks?
No. Two 56-hour weeks would total 112 hours and breach the 90-hour two-week limit.
Does POA count towards the 90 hours?
No. A valid period of availability is not driving time. It is also normally excluded from working time under the sector-specific working-time rules.
Can this calculator replace a tachograph record?
No. It can help explain and estimate recorded totals, but tachograph and employer compliance records remain authoritative.
Checked against the DVSA’s Drivers’ hours and tachographs: goods vehicles — assimilated and AETR rules. Rules can change, and individual circumstances or exemptions may affect which rules apply.
Keep the working week in one place.
CabLog is in private pilot as a personal HGV driver diary for shifts, pay, mileage, expenses and recorded driver-rule totals.
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