Calculator Inputs
All values are monthly unless noted otherwise.
Example Data Table
| Scenario | Forecast Demand | Machines | Cycle Time | Effective Capacity | Capacity Cushion |
|---|---|---|---|---|---|
| Base Plan | 12,000 units | 5 | 6.0 min/unit | 18,972 units | 27.22% |
| Peak Season | 15,500 units | 5 | 6.0 min/unit | 18,972 units | 11.58% |
| Improved Throughput | 15,500 units | 5 | 5.4 min/unit | 21,080 units | 20.54% |
Formula Used
Units per hour = 60 ÷ Cycle Time per Unit
Gross Hours per Machine = (Working Days × Shifts per Day × Hours per Shift) + Overtime Hours
Net Hours per Machine = Gross Hours − Planned Downtime − Setup Hours
Design Capacity = Machines × Gross Hours per Machine × Units per Hour
Effective Capacity = Machines × Net Hours per Machine × Efficiency × Utilization × Units per Hour
Adjusted Demand = Forecast Demand × (1 + Safety Factor) ÷ (1 − Scrap Rate)
Required Hours = Adjusted Demand ÷ Units per Hour
Required Machines = Required Hours ÷ Effective Hours per Machine
Capacity Cushion = (Effective Capacity − Adjusted Demand) ÷ Effective Capacity × 100
Use decimals in the calculator only where needed. Percent fields are automatically converted to planning factors.
How to Use This Calculator
- Enter the monthly demand forecast you want to support.
- Add a safety factor to protect against variation.
- Include scrap, downtime, setup, and overtime assumptions.
- Enter the available machine count and operating schedule.
- Set realistic efficiency and utilization targets.
- Submit the form to view capacity, machine needs, and planning cushion.
- Use the chart to compare future demand against current capacity.
- Download the results as CSV or PDF for reporting.
Frequently Asked Questions
1) What does capacity planning measure here?
It estimates how much output your current machine base can produce each month after schedule limits, downtime, changeovers, efficiency losses, and utilization targets are considered.
2) Why is adjusted demand higher than forecast demand?
Adjusted demand adds safety stock and compensates for expected scrap. This creates a more realistic production target than using forecast demand alone.
3) What is the difference between design and effective capacity?
Design capacity uses total scheduled hours. Effective capacity reduces that ideal figure for downtime, setup losses, efficiency, and utilization realities.
4) When should I increase machine count?
Increase machines when capacity gap is negative, load stays very high, or your cushion becomes too small to absorb downtime spikes and demand swings.
5) Can I use this for staffing decisions too?
Yes. Required hours and machine needs help estimate labor demand, operator coverage, and whether overtime or an extra shift is enough.
6) How should I choose efficiency and utilization?
Use recent actuals, not best-case assumptions. Conservative inputs produce better plans and reduce the risk of chronic shortages.
7) Does overtime fully solve shortfalls?
Not always. Overtime raises gross hours, but bottlenecks, labor availability, fatigue, maintenance, and scrap may still limit practical output.
8) Why is capacity cushion important?
Cushion shows your reserve margin. A healthy cushion helps absorb forecast error, downtime, rush orders, and seasonal peaks without constant firefighting.