Fixed-price projects go wrong when you quote your honest estimate with no room for the work you can't see yet. This builds a defensible quote — a floor, a recommended price, and a worst-case check — and shows what you'd actually earn per hour if the project runs long.
| If you quote… | And it goes to plan | And it gets messy |
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Base hours = your estimate + the revision rounds you're including (included rounds × hours per round). These are the hours you've actually promised.
Recommended quote adds the contingency buffer on top: base hours × (1 + buffer%) × rate. The buffer is the room for scope you couldn't see at estimate time — the single biggest reason fixed bids lose money.
Floor is the same work with no buffer. It's what undercutters quote — and what turns a profitable project into an unpaid one the moment anything slips.
"If it gets messy" doubles the contingency, modeling a realistic bad case.
The table shows your realized hourly rate: quote ÷ hours it actually took. Notice the buffer keeps you near your full rate even when things slip — and quoting the Floor does not.