Roofing Delivery Backlog
Backlog weeks = outstanding sales / weekly completion capacity
Gather a completed job sheet, supplier quotes and a crew schedule. Include materials, disposal, and weather-related downtime. The starting figures are examples. Replace them with your own records.
Formula and worked example
Backlog weeks = outstanding sales / weekly completion capacity
| Input | Example |
|---|---|
| Confirmed outstanding sales | 60 |
| Completed sales per week | 12 |
| Calculated result | 5 weeks |
Choose reliable inputs
Plan materials, travel and crew time before committing to a price. For this roofing calculation, use a completed job sheet, supplier quotes and a crew schedule and a consistent definition of one roofing job.
- Materials: include the portion belonging to this roofing job or reporting period, and record where the value came from.
- Disposal: include the portion belonging to this roofing job or reporting period, and record where the value came from.
- Weather-related downtime: include the portion belonging to this roofing job 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.
Is this an exact promise date?
No. It is an average workload ratio. Actual completion depends on sequencing, resources, and job duration.
Assumes comparable job sizes and no new bookings; priority and scheduling constraints are excluded.
What if this input changes?
If confirmed outstanding sales rises by 10%, this example changes by 0.5 weeks. 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.