How the formula works
Base estimate = hours × hourly rate. Client quote = base × (1 + contingency%). Contingency is a risk line for unknowns — revisions, integration snags, stakeholder delay — not a substitute for a written scope.
Worked example
40 hours at $85/hour is a $3,400 base. A 15% contingency adds $510, so the client-facing quote is $3,910. If the project stays clean, you keep the cushion; if it slips, you had planned for it instead of discounting your weekend.
FAQ
Why add contingency instead of padding hours quietly?
A visible contingency line keeps scope honest. When extras appear, you can point to the buffer or issue a change order instead of eating the work.
What contingency percentage is reasonable?
Clear deliverables often work at 10–15%. Fuzzy discovery or new tech stacks may need 20–30%. If you need more than that, the scope is probably not quote-ready.
Should I show the contingency to the client?
Many freelancers show a single project total and keep the buffer internal. Either way, calculate it on purpose — do not hope the hours were generous enough.
Hourly or fixed after I get this number?
Use the total as a fixed quote when deliverables are crisp. Stay hourly when the client is still deciding what “done” means.
Pair with the rate calculator for your floor, and read how to stop scope creep.