This tool estimates internal cost only. Contract terms and local law determine whether any fee may be charged.
Try this with your own numbersFormula and worked example
Carrying cost = invoice × annual rate × delay days / 365
| Input | Example |
|---|---|
| Unpaid invoice amount | 10,000 |
| Days delayed | 30 days |
| Annual cash carrying-cost assumption | 12 % |
| Calculated result | 98.6301 |
Choose reliable inputs
Include software licences, delivery time, revisions and ongoing support when costing a project. For this web design calculation, use project time logs, licence invoices and retainer scopes and a consistent definition of one project.
- Design hours: include the portion belonging to this project or reporting period, and record where the value came from.
- Development: include the portion belonging to this project or reporting period, and record where the value came from.
- Revisions: include the portion belonging to this project 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.
Can I charge this amount to the customer?
This tool estimates internal cost only. Contract terms and local law determine whether any fee may be charged.
Uses simple interest and a 365-day year; this is not a lawful late-payment fee calculation.
What if this input changes?
If unpaid invoice amount rises by 10%, this example changes by 9.863 . 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.