Scope Creep Cost Calculator
Put a number on unbilled extra work: what scope creep costs you and how much it erodes a fixed-fee project’s margin.
How it works
Creep cost = extra hours × rate · Effective rate = fee ÷ hours · Rate lost % = (planned − actual) ÷ planned × 100
Scope creep is unbilled work absorbed into a fixed fee, and it is expensive precisely because it is invisible. Multiply the extra hours by your rate to see the revenue you effectively gave away. The sharper number is the effective rate: as unbilled hours grow, the same fee spreads over more hours, so the rate you are truly earning collapses even though the invoice never changes. Seeing that drop is the case for a change order.
Worked example
An $8,000 project planned for 60 hours has an effective rate of $133/hour. Twenty extra unbilled hours at $100 is $2,000 of lost value, and the effective rate falls to 8,000 ÷ 80 = $100/hour — a 25% cut.
Frequently asked questions
What counts as scope creep?
Any work beyond what the agreement covered that you deliver without extra pay — added revisions, new features, extra meetings, "quick" favours. Small individually, it compounds into serious unbilled hours on a fixed fee.
How do I stop giving away hours?
Define deliverables and a revision limit in writing, then raise a change order when a request falls outside them. Showing the client the effective-rate impact often makes the case for you.
Why does the fee stay the same but my rate drop?
A fixed fee divided by more hours is a lower rate per hour. The invoice does not move, so the loss hides in your time — which is exactly why scope creep is so easy to miss until the project is unprofitable.
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Educational estimate, not financial advice.