All about Early Start, Early Finish, Late Start and Late Finish

early start early finish late start late finish calculation

This topic is very important from PMP exam perspective. You must expect a question or two based on the calculations of Early Start and Finish and Late Start and Finish.

Also, before we get into the details, it is very important that you have the understanding of the previous concepts that build up this topic, specifically the 3 listed below,

  1. Network Diagrams
  2. Critical Path
  3. Float / Slack

Now, we already know that Float or Slack is the amount of time an activity can be delayed without impacting the project end date. But the early start or early finish and late start or late finish numbers can actually show you how much freedom you really have.

Early Start – The earliest time that an activity can start

Early Finish – The earliest time that an activity can finish

Late Start – The latest time that an activity can start

Late Finish – The latest time that an activity can finish

Each activity in Network Diagram is represented as below,

es ef ls lf float - All about Early Start, Early Finish, Late Start and Late Finish

Also, remember that Float can be calculated with these start and finish values using the formula below,

Float = Late Start – Early Start or Late Finish – Early Finish

Do refer to the video for step-by-step calculation of these values in the example below,

calculation of early start and early finish late start and late finish - All about Early Start, Early Finish, Late Start and Late Finish

Check more articles on Schedule Management

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