Project estimate calculator
Three-point PERT estimation for proposals. Enter optimistic, likely, and pessimistic hours per task — get expected totals, confidence ranges, and a price band. Not sure what to charge? Start with thefreelance rate calculator.
Templates
Tasks
E = (O + 4M + P) / 6 · σ = (P − O) / 6
Estimates are systematically optimistic — Hofstadter's law applies. A 15–25% buffer is honest; 0% is how projects go over budget.
Default 5 productive hours/day, not 8. Meetings, context switching, and admin eat the rest — billing 8h of dev work in an 8h calendar day is fiction.
Per-task expected hours
| Task | E (h) | σ (h) |
|---|---|---|
Total expected
With buffer
~68% range (±1σ)
~95% range (±2σ + buffer)
Timeline
Price range
Proposal summary
About this tool
PERT (Program Evaluation and Review Technique) weights the likely case 4× heavier than the extremes. Project variance combines via root-sum-square — tasks don't all slip by the same amount at once, but some will.
Tasks serialize in the URL when compact enough; longer lists fall back to localStorage. Share the link to align on scope before you send a fixed quote.