Agency Capacity Calculator

How the Capacity Formula Works

Agency capacity planning fails when it starts from headcount. Four people at 40 hours a week is 160 hours on paper, but nobody sells 160 hours — vacations happen, standups happen, proposals get written, and even a fully booked consultant can't bill every working minute. This agency capacity calculator strips the fiction out in three steps:

Gross capacity is the sum of everyone's contracted weekly hours. Subtracting average leave and internal/admin time gives working capacity — hours actually available for any work. Applying a utilization target (the share of working time that realistically converts to billable work) gives sellable hours. Compare that to the client hours you've already committed and you know, in one number, whether you can take the next deal or you're about to burn the team out.

Multiply sellable hours by your average billable rate for weekly revenue capacity, and by 4.33 (average weeks per month) for the monthly figure. Any positive gap between sellable and committed hours, priced at your rate, is revenue capacity you're paying for but not selling.

A Worked Example

Take the calculator's defaults: a four-person team at 40 hours each, 6 hours of average weekly leave across the team, 20 hours of internal/admin time, a 65% utilization target, 85 committed client hours, and a $95 average billable rate.

• Gross capacity: 4 × 40 = 160 hrs/week
• Working capacity: 160 − 6 − 20 = 134 hrs/week
• Sellable hours: 134 × 0.65 = 87.1 hrs/week
• Available to sell: 87.1 − 85 = 2.1 hrs/week — 97.6% booked
• Weekly revenue capacity: 87.1 × $95 = $8,275
• Monthly revenue capacity: $8,275 × 4.33 ≈ $35,829
• Unsold capacity: 2.1 hrs × $95 × 4.33 ≈ $864/month

This team is running tight: 97.6% of sellable capacity is committed, leaving just 2.1 hours of slack per week. One sick day or one scope overrun and delivery slips. The “what if” scenarios show the two levers: hiring one more 40-hour person lifts sellable hours to 113.1/week (about $46,524/month of revenue capacity), while raising the utilization target five points to 70% adds capacity without hiring — sellable hours become 93.8/week.

How Booked Should an Agency Be?

The booked percentage — committed hours as a share of sellable hours — is the single best early-warning gauge an agency has. 70–90% booked is healthy: the team is earning while keeping slack for overruns, sales support, and the unexpected. 90–100% is tight — sustainable for a sprint, corrosive for a quarter, because every overrun comes straight out of evenings and weekends. Over 100% is overbooked: you've sold hours you don't have, and either deadlines or quality will pay for it.

The other direction matters just as much. At 50–70% booked, you're underutilized — payroll runs at full price while a third of sellable time earns nothing. Below 50% is critical: the unsold-capacity number in the calculator tells you exactly how much revenue is evaporating each month, and it's usually the difference between profit and loss for the whole business.

On the utilization target itself: 60–70% is realistic for most agencies once meetings, account management, and context switching are counted honestly. Targets above 80% look great in spreadsheets and produce burnout in practice. If your quoted projects keep overrunning the hours you planned, capacity isn't your only problem — check the pricing side with the fixed price project calculator.

Mistakes to Avoid in Capacity Planning

1. Planning at 100% utilization

If the plan assumes every working hour is billable, the plan is wrong on day one. Standups, email, estimates, and internal reviews consume 25–40% of most weeks. Set the utilization target from measured history, not aspiration.

2. Ignoring leave until it happens

Vacations, public holidays, and sick days average out to a predictable weekly cost — roughly 10–15% of gross hours over a year. Budget it as a standing deduction rather than treating each absence as a surprise.

3. Counting committed hours from memory

Retainers, half-finished projects, and “quick favors” for old clients all consume committed hours. If commitments live in people's heads, the booked percentage is a guess. Pull committed hours from actual tracked time and scheduled work, not gut feel.

4. Selling capacity without pricing it

Filling the calendar is not the goal — filling it at the right rate is. Before selling spare hours at a discount, work out what your team's mixed hours are really worth with the blended rate calculator, and check the deal's margin in the project profitability calculator. Marketplace work should be netted for fees first — the Upwork fee calculator does that in seconds.

5. Hiring on a hunch

Hire when the booked percentage stays above 90% for six-plus weeks and the pipeline supports the new capacity — not because one month felt frantic. The hiring scenario in the calculator shows exactly how much sellable capacity and monthly revenue a new 40-hour hire adds; compare that against their loaded cost before signing the offer.