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Project Estimator

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Breaks down projects into tasks, estimates effort with confidence intervals, identifies dependencies and risks, and produces planning spreadsheets.

By Community 5,900 stars v1.1.0 Updated 2026-03-10
$ Copy the SKILL.md file to your project's .claude/skills/ directory

About This Skill

Project Estimator applies structured estimation techniques to combat the planning fallacy — the universal human tendency to underestimate how long things take. It produces estimates with honest uncertainty ranges, not false precision.

Estimation Methodology

Three-Point Estimation (PERT) For each task, generates three scenarios: - **Optimistic (O)** — everything goes right, no blockers - **Most Likely (M)** — realistic with typical interruptions - **Pessimistic (P)** — significant unknowns or complications

Weighted average: `(O + 4M + P) / 6` with standard deviation `(P - O) / 6`.

Work Breakdown Structure Decomposes the project top-down: - Epic → Feature → Story → Task - Each leaf-level task estimated independently - No single task estimated over 3 days (decompose further if needed)

Confidence Bands Aggregates task estimates into project-level confidence bands: - P50 (50% confidence deadline) - P80 (80% confidence deadline) - P95 (95% confidence deadline)

Delivered with the message: "We're 80% confident this will be done by [date]."

Risk Register

  • Identifies risks alongside estimates:
  • Technical risks (unfamiliar technology, external API dependencies)
  • Resource risks (key person dependency, part-time availability)
  • Scope risks (ambiguous requirements, stakeholder alignment gaps)

Each risk scored by probability × impact with mitigation suggestions.

Output Formats

  • CSV for import into Jira, Linear, or Notion
  • Markdown task list with time estimates
  • Gantt chart description for visualization tools

Use Cases

  • Estimating development sprints and releases for engineering teams
  • Creating project proposals with realistic timelines for clients
  • Breaking down product features into sized user stories
  • Building resource allocation plans for multi-team projects

Pros & Cons

Pros

  • +Three-point PERT estimation provides honest uncertainty ranges
  • +P50/P80/P95 confidence bands for stakeholder communication
  • +Risk register generated alongside estimates
  • +CSV output importable to Jira, Linear, and Notion

Cons

  • -Estimate quality depends on the detail of the project description provided
  • -Does not integrate with actual velocity data from your team's sprint history

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FAQ

What does Project Estimator do?
Breaks down projects into tasks, estimates effort with confidence intervals, identifies dependencies and risks, and produces planning spreadsheets.
What platforms support Project Estimator?
Project Estimator is available on Claude Code, Cursor, Gemini CLI.
What are the use cases for Project Estimator?
Estimating development sprints and releases for engineering teams. Creating project proposals with realistic timelines for clients. Breaking down product features into sized user stories.
What tools work with Project Estimator?
Project Estimator works well with Claude, Notion AI, ChatGPT.

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Next Step

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