How to Calculate Your IT Team Capacity: Complete Formula and Examples

Introduction: Why Calculate Capacity?

Accurately calculating your IT team capacity is fundamental for effective planning and informed decisions. Without this precise measure, it's impossible to know if you can take on new projects, if you need to recruit, or if you should outsource certain activities.

Many IT Directors underestimate or overestimate their capacity, leading to suboptimal decisions: taking too many projects (overload) or not taking enough (underutilization). Precise capacity calculation is the foundation of effective capacity planning.

In this comprehensive guide, we'll explain in detail how to calculate your IT team capacity, with precise formulas, concrete examples, and methods to optimize your calculations.

What is IT Capacity?

IT capacity represents the volume of work a team can accomplish over a given period, taking into account all constraints and limiting factors. It's not simply the number of people multiplied by the number of days, but a complex measure that integrates many factors.

Capacity vs Availability

It's important to distinguish:

• Theoretical capacity: The theoretical maximum (e.g., 8h/day × number of days)
• Available capacity: Real capacity after deducting leave, training, etc.
• Usable capacity: Optimal capacity to use (generally 75-85% of available capacity)

The Basic Capacity Calculation Formula

IT team capacity is calculated according to this fundamental formula:

Capacity = Number of people × Working days × Utilization rate

But this simple formula hides a complexity that must be mastered to obtain precise results.

Detailed Calculation Components

Let's analyze each component in detail:

1. Number of People (FTE)

The number of people must be calculated in full-time equivalent (FTE):

• One full-time person = 1.0 FTE
• One person at 80% = 0.8 FTE
• One person at 50% = 0.5 FTE

Example: A team of 8 full-time people + 2 people at 80% = 8.0 + 1.6 = 9.6 FTE

2. Working Days

Calculating working days is crucial and often underestimated. You must exclude:

• Weekends: On average, 104 days per year (52 weeks × 2 days)
• Holidays: In the US, 10 federal holidays per year
• Paid leave: On average 15-20 days per year in the US
• Training: On average 5-10 days per year per person
• Sick leave: On average 5-7 days per year
• Meetings and administration: On average 10-15% of time

Calculation for a year:

• Calendar days: 365
• Less weekends: 365 - 104 = 261 days
• Less holidays: 261 - 10 = 251 days
• Less leave: 251 - 18 = 233 days
• Less training: 233 - 7 = 226 days
• Less absences: 226 - 6 = 220 days
• Meeting adjustment (× 0.85): 220 × 0.85 = 187 working days per year

For a quarter: 187 / 4 = 47 working days

For a month: 187 / 12 = 15.6 working days

3. Utilization Rate

The utilization rate represents the percentage of time actually productive. It should not be confused with load rate.

Optimal utilization rate:

• 75-85%: Optimal rate for productivity and well-being
• Below 75%: Underutilization, resource waste
• Above 85%: Overload risk, stress, quality decline
• Above 100%: Overload, burn-out, guaranteed delays

Detailed Calculation Examples

Here are concrete examples for different scenarios:

Example 1: Team of 10 People over a Quarter

Data:

• 10 full-time people = 10.0 FTE
• Working days per quarter = 47 days
• Utilization rate = 80%

Calculation: 10 × 47 × 0.80 = 376 person-days

In hours: 376 × 7.5h/day = 2,820 hours

Advanced Factors to Consider

For an even more precise calculation, consider these additional factors:

1. Skill Levels

A senior generally produces 1.2-1.5 times more than a junior. Adjust your calculations according to levels:

• Senior (5+ years): 1.2-1.5 FTE
• Experienced (2-5 years): 1.0 FTE
• Junior (< 2 years): 0.7-0.8 FTE

Tools to Automate Calculation

Manual capacity calculation is complex and time-consuming. Modern tools like Workload automatically calculate capacity by integrating all these factors:

• Automatic FTE according to contracts
• Working days calculated automatically (leave, holidays, etc.)
• Optimal utilization rate suggested
• Capacity by skill
• Real-time updates

Conclusion

Precise capacity calculation is the foundation of effective capacity planning. By mastering these formulas and methods, you'll make informed decisions and optimize your IT resource utilization.

To discover how Workload automates all these calculations and gives you a precise view of your capacity in real-time, try free for 14 days. Setup in 5 minutes, no credit card required.