Use honest inputs
Choose recent costs and realistic capacity instead of the number you hope will be true.
This calculator does not determine a legal late fee or interest entitlement. Use your signed agreement and local law for those decisions.
A number becomes useful when it changes a decision.
Save the assumptions with the project or client record, compare the estimate with actual results, and update the model when your costs or capacity change.
Record the assumptions
A result without its assumptions cannot be reviewed or improved later.
Compare estimate to actual
Use delivered projects and paid invoices to improve the next estimate.
Is this calculator free?
Yes. It runs in your browser and does not require an email address.
Does Stelaah store the values entered here?
No. This page performs the calculation in your browser and does not submit the entered values to Stelaah.
Should I use the result as professional advice?
No. Treat it as a planning estimate and confirm accounting, tax, legal, and commercial decisions with the appropriate professional.
Keep the assumptions with the client work.
Stelaah connects scope, projects, time, budgets, invoices, and decisions.