Accountants Utilisation Rate Formula
Learn how accountant utilisation rate, target billable hours, and the billable-hours gap are calculated.
Accountant utilisation measures the share of available working time recorded to billable client work. Calculating it after deducting leave and unavailable time gives a clearer view of billable capacity for a person or team during a reporting period.
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Utilisation rate
Where:
First subtract leave and other unavailable hours from scheduled hours. Then divide billable client-work hours by the remaining available hours and convert the result to a percentage.
Variables Explained
| Variable | What It Means | Unit |
|---|---|---|
| billableHours - Billable hours | Total hours recorded to billable client work during the reporting period. | hours |
| totalWorkingHours - Total scheduled working hours | Total scheduled hours before leave and other unavailable time is deducted. | hours |
| leaveHours - Leave and unavailable hours | Hours unavailable for client work, such as leave, training, public holidays, or sickness. | hours |
| availableHours - Available hours | Scheduled hours remaining after unavailable time is deducted. | hours |
| targetUtilisationRate - Target utilisation rate | The selected billable-time percentage used as a planning benchmark. | percent |
| targetBillableHours - Target billable hours | Billable hours required to reach the selected target rate. | hours |
| billableHoursGap - Billable hours gap | Difference between target billable hours and actual billable hours. | hours |
Step-by-Step Calculation
Calculate available hours
Remove leave and other unavailable time from scheduled working hours. Available hours cannot be below zero.
availableHours = max(totalWorkingHours - leaveHours, 0)
Calculate the utilisation rate
Divide billable hours by available hours and multiply by 100. Using a minimum divisor of 1 prevents division by zero when no available hours are entered.
utilisationRate = (billableHours / max(availableHours, 1)) * 100
Calculate target billable hours
Multiply available capacity by the target percentage expressed as a decimal.
targetBillableHours = availableHours * (targetUtilisationRate / 100)
Calculate the billable-hours gap
A positive result means more billable hours are needed. A negative result means recorded billable hours are above the selected target.
billableHoursGap = targetBillableHours - billableHours
Monthly accountant utilisation calculation
Available hours
160 - 8
152 hours
Utilisation rate
(120 / 152) × 100
78.9%
Target billable hours
152 × (75 / 100)
114 hours
Billable-hours gap
114 - 120
-6 hours
Final Result
Utilisation is 78.9%. With 152 available hours, 120 billable hours are 6 hours above a 75% utilisation target.
Assumptions
- ✓Billable hours and scheduled hours relate to the same person or team and the same reporting period.
- ✓Available hours equal scheduled hours less leave and other time unavailable for client work.
- ✓Billable time has been recorded consistently under the organisation's time-recording approach.
- ✓The target rate is a planning benchmark rather than a universal performance standard.
Limitations
- !The calculation does not assess the quality, profitability, recovery, or collection of billable work.
- !Results can be distorted by delayed timesheets, work-in-progress adjustments, or hours recorded in a different period.
- !A rate above 100% can occur when billable hours exceed entered available hours because of overtime or incomplete availability records.
- !Utilisation alone does not account for necessary non-billable work such as management, business development, training, or internal administration.
Common Mistakes to Avoid
Using gross scheduled hours as the denominator without deducting leave, training, or public holidays.
Combining billable hours from one period with scheduled hours from another period.
Entering chargeable value or fees instead of actual billable hours.
Treating a negative billable-hours gap as a shortfall rather than hours above target.
Comparing roles with materially different levels of client, management, or internal responsibilities.
Related Formulas
Frequently Asked Questions
What is the formula for accountant utilisation rate?
Utilisation rate equals billable hours divided by available hours, multiplied by 100. Available hours are scheduled hours less leave and other unavailable time.
How do I calculate billable hours needed for a target utilisation rate?
Multiply available hours by the target utilisation rate divided by 100. For example, 152 available hours at a 75% target require 114 billable hours.
Why are leave hours deducted from utilisation?
Deducting leave helps measure billable time against hours that were genuinely available for work rather than against all scheduled hours.
What does a negative billable-hours gap mean?
It means actual billable hours exceed the billable hours required by the selected target. For example, a gap of -6 hours means 6 hours above target.
Can an accountant utilisation rate exceed 100%?
Yes. It may happen when overtime is billed, availability is understated, or time records and scheduled hours cover different periods.
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