Build a project cost estimate with a contingency reserve
A structured cost estimate by work package with explicit assumptions, risk-based contingency, and a range you can defend.
The prompt
Help me build a cost estimate for my project, including a contingency reserve.
Project scope: [SUMMARY or work breakdown]
Labor: [roles, number of people, time on the project, loaded rates if known]
Non-labor costs: [software, hardware, vendors, travel, facilities, training]
Known risks that could add cost: [LIST]
Estimating basis: [past similar projects, vendor quotes, expert judgment]
Currency and budget period: [e.g. USD, fiscal year]
Steps:
1. Organize costs by work package or phase, separating one-time from recurring costs.
2. List every assumption behind each line (rate, duration, quantity) so a reviewer can challenge it.
3. Rate each line's estimate confidence (high / medium / low) based on its basis.
4. Size a contingency reserve from the identified risks (probability x cost impact), and explain why it differs from a flat percentage. Mention that a separate management reserve for unknown risks is usually held by the sponsor, not the project.
5. Flag commonly forgotten costs: internal staff time, licenses after go-live, data migration, testing environments, change management, hypercare.
Rules: do not invent rates or prices. Use [QUOTE NEEDED] or [RATE NEEDED] placeholders. This is planning support, not accounting advice - have finance validate it before approval.
Return:
1. An estimate table: work package | item | quantity | rate | cost | basis | confidence.
2. A contingency table: risk | probability | cost impact | expected value.
3. Totals: base estimate, contingency, and a low-high range.
4. An assumptions list for the business case.
Highlighted [brackets] are blanks to replace with your own details.
Fill in the blanks and use this promptMore Finance & Accounting prompts
What to fill in
- SUMMARY or work breakdown
- software, hardware, vendors, travel, facilities, training
- LIST
- past similar projects, vendor quotes, expert judgment
- e.g. USD, fiscal year
- QUOTE NEEDED
- RATE NEEDED
How this prompt is built
This prompt follows the RTF structure (Role, Task, Format). RTF tells the model who to be, what to do and what shape the answer should take. It is the quickest structure that still gives noticeably better results than a bare request.
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