Billable Hours Calculator
Work out how many hours you can actually bill in a year and what they are worth.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Estimate annual billable capacity from calendar weeks, time off, sick days, weekly admin time and your rate. The model assumes a five-day workweek; it is a planning scenario, not a benchmark for how much any freelancer should bill.
Worked example
calculated with the default values below
Calendar weeks per year (up to 52) 52 · Hours per week 40 h · Holiday taken 4 weeks · Sick and personal days 5 days · Admin, marketing and training per week 10 h · Hourly rate 80 $/h Gross working hours 1,880 h · Non-billable hours 470 h · Billable hours 1,410 h · Billable share 75.0 % · Annual revenue at this rate 112,800 $ · Billable hours per week 30.0 h
General background references
Disclaimer
These calculators give general date results. Public holidays, working-day conventions and time-zone rules are set locally and change, so confirm against the official calendar for anything legally or contractually binding.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
B = max(0, W·H − 8S − A·W)
- W
- Working weeks per year
- H
- Hours worked per week
- S
- Sick/personal days (8 h each)
- A
- Admin/marketing hours per week
- B
- Annual billable hours
One sick day counts as 8 hours; the holidayWeeks input is not applied—set weeks per year already net of holidays; revenue = B × hourly rate.
Frequently asked questions
Why can weekly admin work reduce billable hours so much?
The calculator starts with weeks worked × hours per week, subtracts eight hours for each sick day, then subtracts admin hours per week × weeks worked. Ten admin hours over 48 weeks therefore remove 480 potential billable hours, while five sick days remove 40. It does not have separate marketing or training inputs; include those hours in the admin figure if appropriate.