A client cancelling mid-project is one of the most common ways freelance work goes sideways, and most freelancers either undercharge for it out of awkwardness or overcharge without a clear justification. This calculator gives you a defensible number: the value of what you already delivered, plus a cancellation charge on the part of the project that never happened, so the invoice you send matches what your contract actually promises.
How it works
A kill fee has two separate components, and conflating them is where most disputes start. The first is the value of work completed — the straightforward share of the project total that corresponds to the scope you already delivered. The second is a cancellation charge on the remainder: the portion of the project that was never done, priced at whatever percentage your contract's kill fee clause specifies.
The calculator multiplies your project total by the percent complete to get the value of work completed. It then takes what's left over — the project total minus that completed value — and applies your cancellation rate to that remainder to get the cancellation charge. The kill fee is the sum of the two. Both component figures are rounded to the cent before they're added, so the total you see always matches the two line items you'd actually put on an invoice — no silent rounding drift between what's displayed and what reconciles.
Worked example
Say you're partway through a $10,000 project. You estimate the work is 40% complete, and your contract's kill fee clause charges 50% of the remaining, undone work if the client cancels.
- Value of work completed: $10,000 × 40% = $4,000
- Remaining (unbilled) work: $10,000 − $4,000 = $6,000
- Cancellation charge: $6,000 × 50% = $3,000
- Kill fee to invoice: $4,000 + $3,000 = $7,000
That $7,000 breaks down cleanly on an invoice as two lines: $4,000 for deliverables already handed over, and $3,000 as a cancellation charge covering the work you scoped time for but won't get to do. If the client had cancelled before you started anything — 0% complete — the same 50% rate would apply to the full $10,000, producing a $5,000 kill fee entirely from the cancellation charge. If they cancelled after full delivery, the kill fee would just be the full $10,000, since there's no remainder left to charge a cancellation rate against.
How to interpret your result
This number is only as good as the two percentages you feed it, and both call for judgment rather than a formula. "Percent complete" should reflect scope delivered, not hours logged or calendar days elapsed — a project that's 80% through its timeline but stuck on the hardest 20% of the work isn't 80% complete in any sense that matters for billing. Round down if you're unsure; a defensible lowball is easier to negotiate up than an inflated number is to walk back.
The cancellation rate is a matter of contract, not calculation. If your agreement specifies a kill fee clause with a stated percentage, use that number exactly — this tool just does the arithmetic. If there's no clause and this is a first-time conversation with a client, treat the output as a proposal, not an invoice. The 25-50% range covers most real-world contracts, but industries and individual agreements vary widely, so don't assume this figure is enforceable unless it's actually written down.
Methodology & sources
The formula is workCompletedValue = projectTotal × percentComplete/100; cancellationCharge = (projectTotal − workCompletedValue) × cancelPercent/100; killFee = workCompletedValue + cancellationCharge. This mirrors how kill fee clauses are typically structured in freelance contracts — pay for what's delivered, then apply an agreed cancellation percentage to what's left, rather than treating the whole project total as one lump sum.
Kill fee percentages in the 25-50% range are common in freelance and creative-industry contracts, but actual clauses vary a lot by field and by how the contract defines "remaining work" — see this rundown of must-have freelance contract clauses and this collection of real kill fee clause examples across publishing, design, and production contracts for a sense of the range. If your contract doesn't yet have a kill fee clause, add one before you need it — negotiating a cancellation percentage after a client has already walked is a much weaker position than having it in writing from the start.