Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Additional FTEs needed now
0.51
Current load against capacity
110.1%
Sustainable monthly capacity
581
Hours of headroom (negative = overbooked)
-59
Annual revenue one hire can bill
$202,275
Annual gross profit per hire
$106,275
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
Got your number — what next?
Pick one, it takes 20 secondsHow to use this
- 1Enter current delivery headcount (people).
- 2Enter available hours per person per month (hrs).
- 3Enter sustainable utilization (%).
- 4Enter committed delivery hours per month (hrs).
- 5Enter loaded cost of a new hire ($/yr).
- 6Enter average bill rate ($/hr).
- 7Read your additional ftes needed now on the right — it updates as you type.
- 8Hit Share to keep the scenario or send it to someone.
About this calculator
Hiring too early burns cash on idle capacity; hiring too late costs you the account. This calculator compares your committed monthly delivery hours to the hours your current team can realistically produce at a sustainable utilization, then converts the shortfall into full-time-equivalent hires and shows the revenue each new hire must generate to pay for themselves. It also flags the buffer — how many hours of headroom you have before you're overbooked — so you can see whether the answer is a hire, a freelancer, or a scope conversation. Most agencies should bring on the next person at roughly 85% of sustainable capacity, allowing for ramp time before the crunch actually lands.
Worked example
Using the values the calculator loads with:
Inputs
- Current delivery headcount: 5 people
- Available hours per person per month: 155 hrs
- Sustainable utilization: 75 %
- Committed delivery hours per month: 640 hrs
- Loaded cost of a new hire: 96000 $/yr
- Average bill rate: 145 $/hr
Results
- Additional FTEs needed now: 0.51
- Current load against capacity: 110.1%
- Sustainable monthly capacity: 581.25
- Hours of headroom (negative = overbooked): -58.75
- Annual revenue one hire can bill: $202,275.00
- Annual gross profit per hire: $106,275.00
What each field means
Inputs
- Current delivery headcount (people)
- The current delivery headcount used in the calculation, measured in people. Starts at 5 people so you have a working example on load.
- Available hours per person per month (hrs)
- The available hours per person per month used in the calculation, measured in hrs. Starts at 155 hrs so you have a working example on load.
- Sustainable utilization (%)
- The sustainable utilization used in the calculation, measured in %. Starts at 75 % so you have a working example on load. Accepted range: 10–100 %.
- Committed delivery hours per month (hrs)
- The committed delivery hours per month used in the calculation, measured in hrs. Starts at 640 hrs so you have a working example on load.
- Loaded cost of a new hire ($/yr)
- The loaded cost of a new hire used in the calculation, measured in $/yr. Starts at 96000 $/yr so you have a working example on load.
- Average bill rate ($/hr)
- The average bill rate used in the calculation, measured in $/hr. Starts at 145 $/hr so you have a working example on load.
Results
- Additional FTEs needed now
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Current load against capacity
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Sustainable monthly capacity
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Hours of headroom (negative = overbooked)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual revenue one hire can bill
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual gross profit per hire
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
At what load should I start recruiting?
Start the search around 85% load, because hiring and ramping a delivery person typically takes 8-14 weeks end to end. If you wait until 100%, you'll bridge the gap with overtime or freelancers at worse margin and higher risk of quality slips.
Hire or use freelancers?
Freelancers make sense when the shortfall is under roughly half an FTE, is seasonal, or requires a skill you won't need permanently. Hire when the demand is durable across at least two or three accounts — single-client hires are how agencies get caught out by one churn event.
Why is sustainable utilization below 100%?
Because nobody bills every available hour. Internal meetings, tooling, pitch support, and training consume 20-30% of the week for most delivery staff, and modeling 100% guarantees you'll be structurally overbooked.
What if gross profit per hire is negative?
Then your bill rate is too low for the salary you're contemplating, and hiring makes the P&L worse, not better. Fix the rate or hire at a lower seniority before adding the headcount.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Agency Utilization Rate Target Calculator
Work out the billable-hour utilization your team needs to cover payroll and overhead.
Agency Blended Hourly Rate Calculator
Find the single hourly rate a mixed delivery team has to bill to hit target margin.
Freelancer vs Full-Time Hire Cost Calculator
Compare the annual all-in cost of a contractor against a salaried delivery hire.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Agency Hiring Capacity Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/agency-capacity-plan
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/agency-capacity-plan" target="_blank" rel="noopener">Agency Hiring Capacity Calculator — RevenueLab</a> (2026).</p>
Source: [Agency Hiring Capacity Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/agency-capacity-plan) (2026).