With the illustrative inputs below, the result is 5 weeks.
Try this with your own numbersFormula 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 insulation installation calculation, use a completed job sheet, supplier quotes and a crew schedule and a consistent definition of one installation.
- Insulation: include the portion belonging to this installation or reporting period, and record where the value came from.
- Access: include the portion belonging to this installation or reporting period, and record where the value came from.
- Crew time: include the portion belonging to this installation 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.