OwnerMath

Calculator

Billable Hours Calculator

Estimate realistic billable hours after admin, sales, meetings, sick time, holidays, vacation, and the general capacity drag of running a solo business.

Hours worked and hours billable are not the same thing. Admin, sales, email, proposals, revisions, context switching, and client management are real work even when nobody pays for them directly. This calculator makes that gap visible before the rest of your pricing stack starts lying.

What this includes

  • Gross annual capacity from your actual weekly schedule
  • Time-off subtraction for vacation, holidays, sick days, and slack
  • Weekly non-billable drag from admin, pipeline work, meetings, and ops
  • Optional revenue and hourly-rate pressure tests
  • Warnings for fantasy utilization, missing overhead, and future burnout

Use this when...

  • You are setting a baseline before hourly-rate, quote, or revenue-goal math.
  • You suspect your calendar can support less billable work than your spreadsheet keeps claiming.
  • You want to pressure-test whether a revenue target fits a solo-operator workload.

Do not use this for...

  • Pricing a scoped project by itself. Use the Project Quote Calculator after this.
  • Auditing a finished job after delivery. That is Effective Hourly Rate territory.
  • Pretending unlimited focus, zero admin, and no vacation are serious business assumptions.

Keep these assumptions visible

Most solo operators do not bill anything close to every hour they work.

If your spreadsheet assumes permanent 30-hour billable weeks plus zero admin and no recovery time, the issue is not ambition. The issue is that your denominator is doing performance art.

  • 20 to 25 billable hours per week is credible for many solo operators.
  • Admin, sales, email, and meetings still count even when clients do not see line items for them.
  • Time off is part of capacity planning, not a rounding error.
  • Utilization above the mid-60% range deserves suspicion before celebration.

Capacity assumptions

Hours worked and hours billable are not the same thing. This form makes the missing chunk visible before your pricing math starts lying.

Work schedule

Formatting only. No exchange-rate conversion.

Weeks you are available for work before billable math shrinks further.

Time off and slack

Use this for dead-air weeks, surprise life admin, and capacity drag that never asked permission.

Weekly non-billable drag

Invoices, email, scheduling, bookkeeping, and the glamorous owner bits.

Pipeline work, proposals, follow-up, networking, and all the stuff that keeps next month alive.

Calls, prep, recap, interruptions, and the focus tax nobody invoices separately.

Templates, systems, training, vendor cleanup, and the other business maintenance.

Revenue pressure test
$
$

Used to estimate revenue capacity and whether the revenue target needs more hours than this calendar can support.

Result

Realistic billable hours: 792 / year

That works out to about 17 billable hours per week and 41% billable utilization.

Gross working hours

1,920

The calendar before non-billable work and time off take their cut.

Estimated non-billable

1,128

Admin, sales, meetings, internal ops, sick time, holidays, vacation, and slack.

Billable hours / month

66

A calmer denominator for revenue planning and proposal math.

Time-off days

33

264 hours removed from annual capacity.

Weekly non-billable drag

18

Nobody pays directly for this chunk, but the calendar still does.

Revenue capacity at target rate

$138,600

Based on $175/hr.

Required hourly rate

$158/hr

Needed to hit $125,000 with this billable capacity.

Target-rate pressure test

At $175/hr, you would need 714 billable hours to hit the annual revenue target.

Verdict: Well Protected

The plan leaves room for admin, sales, and recovery while still supporting useful billable capacity. That is how a business behaves when it respects physics.

Warnings

  • info

    Current capacity supports the revenue target

    At $175/hr, this capacity supports about $138,600 in annual revenue.

Next action

Use this capacity in your revenue and quote math

Carry the realistic billable-hours number into your revenue target, hourly floor, and project quote decisions so the rest of the system stays honest.

Visible assumptions

Gross capacity base
Working weeks x days per week x hours per day
Non-billable work includes
Admin, sales, meetings/context switching, and internal ops
Time-off subtraction
Vacation + holidays + sick days + buffer days
Billable utilization formula
Billable hours per year รท gross working hours per year
Currency handling
Formatting only in USD. No exchange-rate conversion.

Educational estimate only. Not tax, legal, accounting, or staffing advice.

What this calculator is actually doing

It starts with gross working capacity, then subtracts the work nobody invoices directly and the days you are not available to work at all. What remains is a billable-hours number you can actually use in revenue planning, hourly-rate math, and fixed-fee quotes without acting surprised later.

Why this number matters

If you tell yourself you can bill 1,400 hours a year when your real calendar only supports 800 to 1,000, every downstream decision gets softer than it looks. Your hourly floor comes out too low. Your project quotes look generous. Your revenue target appears reasonable right up until your week starts eating evenings.

This is not about pessimism. It is about distinguishing between work that keeps the business running and work a client actually pays for. Both are real. Only one makes the invoice.

Formula and assumptions

Gross working hours = working weeks x days per week x hours per day.

Estimated non-billable hours = weekly admin + sales + meetings/context switching + internal ops, multiplied across the year, plus vacation, holiday, sick, and buffer days converted into hours.

Realistic billable hours = gross working hours - estimated non-billable hours.

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