The complete guide to agency capacity planning

You have 5 people. Total billable capacity per week: 160 hours.

You're fully booked most weeks. Sometimes over-booked. When new projects come in, you squeeze them in or push out deadlines.

That's not a business. That's chaos.

Capacity planning means knowing exactly how many hours you have available, what you're committed to, and how far out you can take new work. It turns chaos into predictability.

The Core Metrics

Three numbers matter:

1. Total Billable Capacity

Start with: Team size x 40 hours per week = baseline capacity.

5 people x 40 = 200 hours per week.

But remove non-billable time:

Meetings and admin: 5 hours/week per person
Professional development: 1 hour/week per person
Vacation and sick time: Varies by policy, average 3 weeks/year

After adjustments:

5 people x (40 - 5 - 1) + vacation buffer = roughly 150-160 billable hours/week.

This is your hard ceiling. You can't exceed it without burning people out.

2. Current Allocation

How many of those 160 hours are committed to existing projects?

Pull this from your PM tool (Asana, ClickUp, Linear, Monday). Sum the hours allocated to each project through their duration.

Example week:

Project A: 50 hours
Project B: 45 hours
Project C: 30 hours
Total: 125 hours
Available: 160 - 125 = 35 hours

3. Runway

When do your current commitments end?

If all committed work ends in 8 weeks, you have an 8-week runway.

If you take on a 10-week project in week 2, it won't fully free up your team until week 12.

Runway answers: How far out can I commit new work before resource conflicts?

The Forecasting Spreadsheet

Build one:

Week	Project A	Project B	Project C	Total Allocated	Available	Runway
1-4	50 hrs	45 hrs	30 hrs	125 hrs	35 hrs	On track
5-8	50 hrs	20 hrs	--	70 hrs	90 hrs	Capacity open
9-12	--	--	--	0 hrs	160 hrs	Fully free

This tells you:

Weeks 1-4: Nearly full. Take small projects only.
Weeks 5-8: 90 hours available. Can take a 6-week project starting week 5.
Weeks 9-12: Fully available. Can take big new projects.

Update this every week. New projects, scope changes, people leaving. Keep it current.

Utilization Targets

Not all agencies aim for 100% utilization. Healthy targets are:

80-85% utilization: Recommended. Leaves buffer for unexpected work, quality focus, and team breathing room.
90%+ utilization: Consistently over-booked. People burn out. Quality suffers. Deadlines slip.
70% utilization: Inefficient. Excess capacity eating into margin.

Most agencies target 80-85%.

Track actual utilization monthly:

Total billable hours logged / Total billable capacity available = utilization %.

If you're consistently at 95%+, you need to hire or raise prices. If you're at 60%, you need more clients or smaller team.

The Conversation With Sales

Capacity planning only works if sales respects it.

Here's the process:

Sales person gets an inquiry for a 12-week project. They ask: "When can we start?"

They check the capacity forecast. If weeks 1-8 are over-booked, the answer is: "We can start in week 9, which is 6 weeks from now."

This prevents sales from promising what ops can't deliver.

Bad version: Sales promises week 1 start. Ops scrambles. Someone gets overloaded. Quality suffers.

Good version: Sales says week 9. Client waits 6 weeks. Project delivers on time. Everyone is happy.

Sales might not love this. They want to close deals immediately. But a delayed start is better than a missed deadline.

The Buffer System

Don't allocate 100% of your capacity. Keep 15-20% unallocated.

Why? For:

Unexpected client requests
Quality work (refactoring, testing, refinement)
Team development (mentoring, learning, improvement)
Operational overhead (strategy planning, process improvement)

This buffer is essential. It prevents the system from breaking when something unexpected happens.

Allocation = (Current projects) + (Buffer) + (Available for new work)

Example:

160 hours/week total 100 hours current projects 25 hours buffer 35 hours available for new work

If new projects consume the 35, you're at 85% utilization. Good.

If sales pushes you to allocate more, you're touching the buffer. That's a problem.

Managing Overflow

Sometimes projects run over. Someone gets sick. A deadline slips. You need extra capacity.

Options:

1. Extend deadlines: Renegotiate scope and timeline. Most clients prefer this.

2. Bring in contractors: For overflow, hire freelancers. Costs more but preserves team health.

3. Reduce scope: Deliver the essential features on time and defer nice-to-haves.

4. Parallel teams: Assign people from other projects. Usually causes context-switching problems.

Option 1 is best. Option 2 is acceptable. Options 3 and 4 are last resort.

Capacity Planning With Variable Scope

Some projects have uncertain scope. How do you plan when you don't know the hours?

Use ranges:

Best case: 60 hours
Likely case: 80 hours
Worst case: 100 hours
Budget: 90 hours (between likely and worst case)

This protects you. If it comes in at 80, you're ahead. If it's 100, you hit your budget.

As you work with clients, collect data. That project you thought was "80-100 hours"? It's always 95. Update your estimates.

Capacity Planning Tools

Spreadsheets work for small teams. For larger agencies, tools help:

Asana and ClickUp: Have resource management features. Track allocation per person.
Monday.com: Includes capacity planning modules.
Kantata, Mavenlink: Dedicated resource management tools.

The tool doesn't matter as much as the discipline. Pick one and use it consistently.

The Forecasting Conversation

Every quarter, sit with your team and forecast the next 3 months.

Ask:

What projects are committed?
When do they end?
Are there any risks (key person leaving, scope uncertainty)?
Do we have capacity for new work?
Where are our constraints?

This conversation surfaces problems early. You find out Sarah's leaving in month 2. You know Project B is at risk. You see that weeks 5-8 are overbooked.

Early visibility means you can adjust. Late visibility means you're reacting to crisis.

Red Flags

Watch for:

Consistent overtime: If people are working 50-hour weeks regularly, your planning is wrong.
Missed deadlines: If you're consistently late, capacity is overallocated.
Low quality: If QA time is being cut to fit schedule, you're over-booked.
High turnover: If people are leaving, burnout is probably the cause.
Scope creep: If projects are always expanding, your scoping or estimation is broken.

None of these are personal failures. They're signals that your capacity planning system isn't working.

FAQ

Q: What if I have retainers that vary in hours month to month? A: Use historical averages. If a retainer is "20 hours per month," but it's actually 15-25 depending on month, use 20 as your baseline and carry a 5-hour buffer for volatility.

Q: How do I account for people working on multiple projects? A: Add up their total allocation across all projects. If Sarah is 25 hours on Project A and 15 hours on Project B, she's allocated 40 hours (100%). Don't double-count.

Q: Should I always keep people fully allocated? A: No. 80-85% utilization is healthier. It leaves room for quality, learning, and unexpected requests. 100% allocation is fragile.

Q: What if my team size changes mid-quarter? A: Update your capacity immediately. If you hire someone, add their hours. If someone leaves, reduce your capacity until you replace them.

Q: How far out should I forecast? A: 3 months is minimum. 6 months is better. Beyond 6 months, uncertainty is too high for accurate forecasting.