Required manpower calculator
How many operators an order needs to be sewn in the working days available, given the garment SMV and the efficiency the line will really run at.
How this is calculated
The order contains quantity × SMV standard minutes. Each operator earns days × hours × 60 × efficiency standard minutes in the period. Operators required = quantity × SMV ÷ (days × hours × 60 × efficiency), rounded up to whole people.
Worked example. 5,000 pieces × 12 min = 60,000 standard minutes. One operator earns 5 × 480 × 0.60 = 1,440 minutes in 5 days. 60,000 ÷ 1,440 = 41.67, so 42 operators.
Questions
- Why round up rather than to the nearest whole number?
- Rounding down leaves the order short. The exact figure is shown too, so you can decide whether a fraction is better covered by overtime than by an extra operator.
- Does this include absenteeism?
- No. It is the number of operators who must actually be working. If your line runs at 8% absenteeism, roster more people accordingly.
- Does the line balance work out with this many people?
- This is a total-minutes estimate. Whether that headcount can be balanced across the operations depends on the bulletin and the bottleneck operation; use it to size the line, then balance it.
Sources & verification
This is the capacity identity of work study rearranged for headcount (ILO, Introduction to Work Study). The worked example is recomputed in the automated tests.