1. What is Slack Time?

Slack time, also called float, is the amount of time a task can be delayed without delaying the project's completion. It's calculated as the difference between late start and early start (or late finish and early finish) of an activity.

2. How Does the Calculator Work?

The calculator uses the slack time formula:

Where:

• \( LS \) — Latest Start time
• \( ES \) — Earliest Start time
• \( LF \) — Latest Finish time
• \( EF \) — Earliest Finish time

Explanation: Activities with zero slack are on the critical path. Positive slack indicates how much delay is possible without affecting project completion.

3. Importance of Slack Time

Details: Slack time helps project managers identify critical activities, allocate resources efficiently, and understand scheduling flexibility.

4. Using the Calculator

Tips: Enter all four values (LS, ES, LF, EF) in consistent time units. The calculator will verify both calculation methods give the same result.

5. Frequently Asked Questions (FAQ)

Q1: What does zero slack mean?
A: Zero slack indicates a critical activity - any delay will delay the entire project.

Q2: Can slack be negative?
A: Negative slack indicates the project is behind schedule and needs acceleration.

Q3: How is slack different from free float?
A: Total slack affects project completion, while free float only affects the next activity.

Q4: What's a typical slack time value?
A: It varies by project, but non-critical activities often have slack ranging from days to weeks.

Q5: How to reduce slack time?
A: Reallocate resources to critical path activities or resequence tasks to optimize the schedule.