Reading the Nodes

Task Name

ES/EF: Earliest Start / Finish

LS/LF: Latest Start / Finish

TE: Expected Time (Avg Duration)

SL: Slack / Float Time

A Red Border indicates the node is on the Critical Path (Slack = 0). You can drag the graph to pan, use your mouse wheel or bottom controls to zoom, and arrows flow left-to-right following dependencies.

Import JSON

Work Breakdown Structure

ID	Task Name	O / M / P	TE	ES	EF	LS	LF	Slack	Actions

What is PertChart.app?

PertChart.app is a free, browser-based project management tool designed to help professionals and students calculate project timelines using the Program Evaluation and Review Technique (PERT).

Unlike heavy desktop software, our tool runs entirely locally in your browser. All your data is processed securely on your machine, ensuring your project timelines remain completely private. Whether you are studying for the PMP exam, planning a construction project, or mapping out a complex software development life cycle, PertChart.app provides an intuitive infinite canvas to visualize your critical path efficiently.

Core Features

Automatic CPM Calculation: Instantly traces the Critical Path Sequence and calculates precise slack/float metrics.
3-Point Estimation: Uses Optimistic, Most Likely, and Pessimistic (O/M/P) inputs for PMBOK-compliant Expected Time.
Infinite Canvas: Pan and zoom effortlessly around complex network dependency diagrams with hardware-accelerated rendering.
Offline & Secure: No signups required. Freely export and import standard JSON files to save and share your work.

What is a PERT Chart?

The Program Evaluation and Review Technique (PERT) is a project management tool used to map out the sequence of tasks required to complete a project. It specifically excels at identifying the Critical Path—the longest continuous sequence of tasks that determines the absolute minimum time needed to complete the project.

Unlike standard Gantt charts, PERT charts use probabilistic time estimation, allowing project managers to account for uncertainty and risk by averaging Optimistic (O), Most Likely (M), and Pessimistic (P) durations.

Why use PERT? (Benefits)

Risk Mitigation: Identifies bottlenecks before they derail the timeline.
Resource Allocation: Slack (Float) values reveal where resources can be safely diverted without delaying the project.
Dependency Mapping: Enforces rigorous left-to-right logic for complex workflows.

Method Comparison

PERT vs Gantt Chart: Gantt charts focus on absolute calendar dates and visual timelines. PERT focuses entirely on logical dependencies and critical path sequence.
PERT vs Standard CPM: Standard Critical Path Method (CPM) uses single deterministic time estimates. PERT uses statistical 3-point estimates to handle uncertainty.
PERT vs Agile: Agile is iterative and flexible. PERT is a predictive (waterfall) planning tool best for projects where dependencies are rigid (e.g., Construction, Operations).

PMBOK Time Estimation

PertChart.app adheres to Project Management Body of Knowledge (PMBOK) best practices by utilizing the Beta Distribution formula for Expected Time (TE).

TE = (Optimistic + 4 × Likely + Pessimistic) / 6

This weighted average places emphasis on the "Most Likely" scenario while statistically softening extreme Optimistic or Pessimistic outliers.

PERT Chart Best Practice Checklist

Define milestones first: Outline major project phases before diving into granular task-level nodes. Avoid dependency loops: Ensure all arrows strictly flow forward to prevent impossible logical circles. Collaborative estimating: Do not guess alone; ask the actual workers to provide the O, M, and P estimates. Monitor the Critical Path: Resources should be heavily guarded on critical tasks since any delay shifts the final project deadline.

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