Plumbing service Capacity with a Contingency Buffer
Deliverable units = floor(hours × (1 − buffer) / hours per unit)
Gather a completed job sheet, supplier quotes and a crew schedule. Include fittings, access time, and travel. The starting figures are examples. Replace them with your own records.
Formula and worked example
Deliverable units = floor(hours × (1 − buffer) / hours per unit)
| Input | Example |
|---|---|
| Available delivery hours | 640 |
| Hours reserved for disruption | 15 % |
| Hours per service visit | 4 |
| Calculated result | 136 units |
Choose reliable inputs
Plan materials, travel and crew time before committing to a price. For this plumbing service calculation, use a completed job sheet, supplier quotes and a crew schedule and a consistent definition of one service visit.
- Fittings: include the portion belonging to this service visit or reporting period, and record where the value came from.
- Access time: include the portion belonging to this service visit or reporting period, and record where the value came from.
- Travel: include the portion belonging to this service visit or reporting period, and record where the value came from.
Use the same currency for every money input. Do not mix weekly costs with monthly revenue, or count the same expense in both an itemised cost and allocated overhead.
Should every available hour be sold?
The reserve is your scenario assumption; it is not a universal staffing recommendation.
What if this input changes?
If available delivery hours rises by 10%, this example changes by 13 units. This shows the effect of one change; it does not predict what will happen.
Open the calculator, save your baseline, then change the input supported by the least reliable estimate in your records. Compare both scenarios before committing to a price or capacity promise.