Accountants Overhead Cost Formula
Learn how monthly accounting practice overhead, break-even revenue, profit-margin revenue, and target hourly rates are calculated.
This calculation estimates the regular monthly cost of operating an accounting practice and converts that cost into revenue and hourly-rate targets. It helps show how much the practice must bill to cover listed overheads and retain a selected profit margin.
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Monthly Revenue Target
Where:
First total all recurring monthly overhead costs. Then divide that total by the share of revenue that remains after the desired profit margin.
Variables Explained
| Variable | What It Means | Unit |
|---|---|---|
| staffCosts - Staff costs per month | Monthly salaries, employer costs, contractors, and regular staff benefits. | currency |
| officeCosts - Office and utilities per month | Monthly rent, utilities, cleaning, supplies, and property-related costs. | currency |
| softwareCosts - Software and subscriptions per month | Monthly costs for accounting software, practice tools, cloud services, and subscriptions. | currency |
| insuranceProfessionalCosts - Insurance and professional costs per month | Monthly insurance, memberships, regulatory costs, and training costs. | currency |
| marketingOtherCosts - Marketing and other costs per month | Monthly marketing, travel, banking, telephone, and other recurring operating costs. | currency |
| totalMonthlyOverhead - Total monthly overhead | The sum of the entered recurring monthly cost categories. | currency |
| billableHours - Expected billable hours per month | Combined hours expected to be charged to clients during the month. | hours |
| targetProfitMargin - Target profit margin | Desired profit retained after the listed overhead costs, expressed as a percentage of revenue. | percent |
| targetMonthlyRevenue - Target monthly revenue | Revenue needed to cover overhead and retain the chosen profit margin. | currency |
Step-by-Step Calculation
Add recurring monthly costs
Combine each regular monthly cost category to find the practice's estimated overhead.
totalMonthlyOverhead = staffCosts + officeCosts + softwareCosts + insuranceProfessionalCosts + marketingOtherCosts
Calculate overhead per billable hour
Spread total overhead across expected client-billable hours.
overheadPerBillableHour = totalMonthlyOverhead / max(billableHours, 1)
Find break-even revenue
Before profit, the revenue required to cover the listed overhead is equal to total overhead.
breakEvenMonthlyRevenue = totalMonthlyOverhead
Convert the profit margin to a revenue share
This is the portion of target revenue available to cover overhead after reserving the selected margin.
costShareOfRevenue = 1 - targetProfitMargin / 100
Calculate the revenue target
Divide overhead by the cost share of revenue to include the desired profit margin.
targetMonthlyRevenue = totalMonthlyOverhead / costShareOfRevenue
Calculate the target average hourly rate
Divide target monthly revenue by expected billable hours to estimate the average required billing rate.
targetHourlyRate = targetMonthlyRevenue / max(billableHours, 1)
Example: monthly overhead and target rate for a small accounting practice
Total monthly overhead
12000 + 2500 + 1200 + 800 + 1500
$18,000 per month
Overhead per billable hour
18000 / 300
$60.00 per hour
Break-even monthly revenue
18000
$18,000 per month
Revenue share available for costs
1 - 20 / 100
0.80 or 80%
Target monthly revenue
18000 / 0.80
$22,500 per month
Target average hourly rate
22500 / 300
$75.00 per hour
Final Result
Estimated monthly overhead is $18,000. The break-even revenue is $18,000 per month, while a 20% target margin requires $22,500 per month, or an average of $75.00 per billable hour.
Assumptions
- ✓All entered cost categories are recurring monthly operating overheads.
- ✓Billable hours are realistic estimates of hours that can be charged to clients in the month.
- ✓The target profit margin is measured as profit divided by revenue after the listed overhead costs.
- ✓All relevant recurring costs are included consistently in one of the input categories.
Limitations
- !The calculation does not automatically include taxes, debt repayments, owner distributions, or client-specific delivery costs.
- !Actual revenue may vary because client work, write-offs, recoveries, and collection timing can differ from planned billable hours.
- !A single average hourly rate may not reflect a practice that uses fixed fees, mixed service pricing, or different team charge-out rates.
- !One-off purchases and irregular annual costs can affect results unless they are included or allocated across months.
Common Mistakes to Avoid
Using total working hours instead of client-billable hours, which can understate the required hourly rate.
Leaving out employer costs, contractor costs, subscriptions, memberships, or bank charges.
Treating break-even revenue as a profit target rather than the amount needed to cover listed overhead.
Entering a profit margin of 20 as though it means adding 20% to costs; the formula treats margin as a percentage of revenue.
Using an overly optimistic billable-hours estimate without allowing for administration, leave, training, and business development.
Related Formulas
Frequently Asked Questions
How do you calculate accounting practice monthly overhead?
Add recurring staff, office, software, insurance, professional, marketing, and other operating costs for the month.
What is the formula for overhead per billable hour?
Divide total monthly overhead by expected monthly billable hours: totalMonthlyOverhead / billableHours.
Is break-even revenue the same as monthly overhead?
In this estimate, yes. Break-even revenue equals the listed monthly overhead before profit and unlisted costs.
How is a 20% profit-margin revenue target calculated?
Divide overhead by 0.80, because 80% of revenue is available to cover costs when 20% is retained as profit.
Why does the required hourly rate rise when billable hours fall?
The same monthly overhead must be recovered over fewer chargeable hours, increasing the overhead and revenue required per hour.
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