Capacity Planning Calculator
Compare available capacity against forecast demand, calculate utilisation, and determine how much additional resource is required to close a gap.
🏭 Operations📐 Capacity = resources × hours × efficiency; utilisation = demand / capacity💼 Business
Number of resources (people or machines)
Available hours per resource per period
Efficiency factor (%)
Forecast demand (hours of work)
Target utilisation (%)
Demand growth expected (%)
Please enter valid values.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| Capacity Planning Calculator | — | Capacity = resources × hours × efficiency; utilisation = demand / capacity | units or hours |
Step-by-Step Examples
Example 1
Over Capacity
12 resources, 160 hours each, 85% efficiency, demand 1,750 hours, 85% target, 25% growth.
- Effective capacity = 12 × 160 × 0.85 = 1,632 hours
- Utilisation = 1,750 / 1,632 = 107.2%
- Shortfall = 118 hours ≈ 0.87 additional resources
- For 85% utilisation: 15.14 resources needed
- At 25% growth: 18.93 resources required
✓ 107.2% — over capacity
Example 2
Healthy Utilisation
10 resources, 150 hours, 90% efficiency, demand 1,080 hours.
- Capacity = 1,350 hours
- Utilisation = 80.0%
- Spare capacity of 270 hours provides buffer for variability
✓ 80.0% — healthy
Example 3
Underutilised
15 resources, 160 hours, 85% efficiency, demand 1,200 hours.
- Capacity = 2,040 hours
- Utilisation = 58.8%
- Spare capacity 840 hours — resources are underused
✓ 58.8% — underutilised
Real-World Applications
Hiring Decisions
Comparing forecast demand against effective capacity gives a quantified basis for headcount or equipment decisions.
Utilisation Ceiling
Running above 90% leaves no slack for absence, variability, or maintenance, and small disruptions cascade.
Growth Planning
Modelling demand growth against capacity shows how far ahead resource decisions must be made.
Efficiency Factor
Theoretical capacity overstates reality — the efficiency factor accounts for setup, breaks, and non-productive time.
Common Mistakes to Avoid
⚠️
Planning to 100% utilisation
Full utilisation leaves no capacity for variability, absence, or maintenance. Queues grow rapidly as utilisation approaches capacity.
⚠️
Using theoretical rather than effective capacity
Raw hours ignore setup, breaks, training, and downtime. The efficiency factor is what makes the number usable for planning.
⚠️
Ignoring the lead time on adding capacity
Hiring and equipment procurement take months. Capacity decisions must be made well before the shortfall arrives.
Frequently Asked Questions
How do I calculate capacity? ▾
Multiply the number of resources by available hours per resource, then apply an efficiency factor to reflect realistic productive time.
What utilisation should I target? ▾
Commonly 80 to 90%. Above that, queues and delays grow sharply as there is no slack to absorb normal variability.
Why does queuing worsen near full utilisation? ▾
Queue length rises non-linearly as utilisation approaches 100%, so small increases in demand near the ceiling cause disproportionate delays.
What efficiency factor should I use? ▾
It depends on the process — typically 75 to 90% once breaks, setup, meetings, and non-productive time are accounted for.
How far ahead should capacity be planned? ▾
At least the lead time to add capacity, which for hiring is often three to six months and considerably longer for equipment.