How to use this calculator
- Enter all hours available in a normal workweek.
- Subtract recurring non-billable responsibilities.
- Allow for weeks when you will not work.
- Choose a realistic booking level and calculate.
#2626 · Salary & HR Tool
Virtual Assistant Billable Capacity Calculator
Estimate how many client hours a virtual assistant can realistically sell in a year after allowing for client support, inbox and calendar work, coordination, and business administration. The result combines weekly availability, non-billable time, time off, and a target booking level, then shows annual, monthly, and weekly capacity for workload and revenue planning.
Calculator
Schedule and utilizationFormula
Annual billable capacity = (weekly hours − non-billable hours) × (52 − weeks off) × booking level
Effective utilization applies the booking level to the billable share of total working time.
What the result means
Use the result as the maximum client workload your schedule can support while preserving the non-billable time and breaks you entered.
Capacity is a planning estimate. Deadlines, uneven demand, and client communication can change the hours available in any month.
Example calculation
At 40 weekly hours, 12 non-billable hours, 5 weeks off, and 85% booking, capacity is 1,118.6 hours a year, or about 93.2 hours a month.
Tips for better results
- Track small client requests and context switching; both can reduce the hours you can reliably sell.
- Use a conservative booking level for a new or seasonal practice.
- Recalculate after adding a large retainer or internal responsibility.
- Leave room for urgent work instead of selling every theoretical hour.
Frequently asked questions
Should proposal and admin time count as billable capacity?
No. Put recurring proposal, admin, and internal work in non-billable hours unless a client contract explicitly pays for it.
How should I account for partially booked weeks?
Use the target booking level to reduce potential billable hours instead of treating every working week as fully sold.
Does this calculator include vacation and public holidays?
Yes, if you include those periods in weeks unavailable. Convert scattered days to fractions of a week when needed.
Can I use monthly working hours instead?
Convert monthly hours to a weekly average first, or use the displayed monthly result after entering a representative weekly schedule.
Why is billable capacity lower than total working hours?
Non-billable duties, time off, and unbooked capacity all reduce the hours that can realistically be invoiced.
Related calculators
Capacity variables
| Variable | Meaning |
|---|---|
| Potential weekly hours | Total hours minus non-billable work |
| Working weeks | 52 minus unavailable weeks |
| Booking level | Expected sold share of potential hours |