start to finish relationship

Start to Finish Relationship In Project Management: Meaning & Examples

Start to Finish Relationship in Project Management

start to finish

In this article, I have defined and explained Start To Finish Logical Relationship with the help of Project Network Diagrams, Gantt Charts & Examples. Start to Finish (SF) is one of the four relationships described in Precedence Diagramming Method (PDM).

The other three are:

  1. Finish to Start (FS)
  2. Start to Start (SS)
  3. Finish to Finish (FF)

These are used to represent and analyze project schedule. This concept originated with PDM. However, by using modern scheduling tools like MS Project and Primavera, you can pictorially represent them on Gantt Charts as well. These relationships are sometimes referred to as project dependencies but former is a better term.

Definition of Start to Finish Relationship

Start To Finish is a Logical Relationship in which a Successor Activity cannot finish until a Predecessor Activity has started.


In simple words we can say that, the Finish of a Successor Activity is Dependent on Start of the Predecessor Activity.

The most common and natural relationship is Finish to Start (FS). Some authors (incorrectly) claim that FS and SF are essentially same. However, it is not true. Even though it is mathematically possible to transform SF to FS to achieve the same result, one should not modify and tamper with natural logic. In real world, SF is very rarely used. You can read FS vs. SF for more details.

You can also look at Max Wideman’s Glossary for a complete set of definitions on PDM.

Project Network Diagram Representation

Let us consider two activities A and B.

  • Duration of A – 3 days
  • Duration of B – 1 day
  • B has a SF relationship with A
  • B’s Finish is dependent on A’s Start – B can Finish (F) as soon as A Starts (S).

start to finish

In the above example, the Project Team would need a total of 4 days to complete these activities.

Gantt Chart Representation

start to finish

Mathematical Representation And Formulas

If you are using 0 method

B(F) = A(S)

Or, if you are using 1 method

B(F) = A(S) – 1

Start To Finish Examples

  • A – Duty of Evening Guard (E), B – Duty of Morning Guard (M). M cannot Finish her/his duty till E Starts. M cannot abandon the post.
  • A – Start using New Software System (N), B – Phase out Old Software System (O). It is assumed that N & O cannot be used in parallel.

Over To You

SF is not a very difficult concept to understand. But sometimes it is confused with FS. After reading this article, do you still have a question(s)?

Do you think this is useful in real projects? Have you ever used it in you project(s)?

Please leave a comment.

Related Articles

0 and 1 Method To Solve Network Diagrams
What are Project Dependencies
4 Types of Project Dependencies
Lead vs Lag
FAQs on Lead and Lag

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6 thoughts on “Start to Finish Relationship In Project Management: Meaning & Examples”

  1. Good article, but one instance that you hadn’t considered in your explanation which is more often used in my arena: When you develop a project schedule with a Finish Date in mind (customer defined requirement for Launch Date). In “working backwards from the end date” planning, the SF dependency is used quite a bit.

    If you have a better suggestion than SF dependencies in this scenario, I’d like to hear about it.

    • Hi Bob,

      The relationships do not change whether you “Schedule From Start Date” or “Schedule From Finish Date”. I suspect most of your relationships would be FS. Plese note that these are Logical relationships and not mathematical relationships.

      I think you may want to read more about constraints like “As soon as possible” and “As late as possible” if you using a tool like MS Project.

      You should also read more about the network diagrams. You can start with:
      Need for a SF relationship –
      Project Network Dagram explaned –


  2. Can you give a concrete example in construction wherein the predecessor must start before a successor could finish. I saw one in the internet, eg. the installation of a new pipeline wherein the old pipeline must start to complete the new pipeline. However it did not specified lag scenario, can you illustrate that too?

    Also in your Gantt illustration, activity A seems to be the successor making activity B the predecessor.


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