What is Float in Project Management?

Experienced project managers are aware that even the best-laid plans can backfire. Those project managers utilize float to control delays and drive the project towards on-time completion rather than allowing a delayed job to derail the entire project and disrupt delivery. However, what does project management float mean? And what role does float play in supporting different project management frameworks for PMs?

What is Float in Project Management?

What is Float in Project Management?

“Float” in project management means the amount of time that a task or a project takes without causing a delay in the project’s overall completion. It represents the flexibility or “buffer” available for a specific task within the project schedule.

Types of float

There are two types of float:

• Total Float
• Free Float

Total Float (or Total Slack)

• Total float is the amount of time that a job can be delayed without affecting the finalization date of a project.
• It is a crucial concept in project management and is often referred to as “project float.”
• Total float represents the flexibility or slack available for a particular task within the project schedule.

Free Float (or Free Slack)

• Free float is the amount of time a task can be delayed without delaying the start of any dependent tasks or tasks on its path.
• Unlike total float, free float is specific to an individual task and does not impact the overall project completion date.
• Project managers may refer to free float less often than total float in discussions about project schedules.

Float Free = Monitoring of the start of the next task – End of the current task – Time.

Float is an important part of the critical path method (CPM), a tool that project managers use to schedule project activities smartly.

What Is the Critical Path?

Critical Path Method (CPM) is a method used in project planning, generally for project scheduling for the on-time completion of the project. It helps in the determination of the earliest time by which the whole project can be completed.

How to calculate float in project management?

Before you can figure out how much flexibility your project tasks have, you need to identify and map which tasks are crucial (critical path) and which ones are not (non-critical) in your project plan. The critical path tasks depend on each other, meaning there’s no leeway or float in their schedules. However, in more intricate projects with multiple task paths, float becomes important in the non-critical paths.

To calculate Total Float: Subtract the task’s earliest finish (EF) date from its latest finish (LF) date. This formula looks like either LF – EF or LS – ES, both giving you the task’s total float.

Total Float = LF – EF or Total Float = LS – ES ( Both of these formulas will give you the task’s total float. )

Where LF stands for latest finish date, EF stands for task’s earliest finish date, ES stand for task’s earliest start and  LS stand for latest start date.

An example of float in project management

Let’s consider a scenario where you’re organizing a birthday celebration, and you have a fixed deadline of 30 days to get everything ready. The critical path activities directly tied to the celebration date are:

1. Invitation Sending
2. Cake Ordering
3. Venue Decoration
4. Food Catering

These tasks form the critical path because they are time-sensitive and must happen in sequence. Any delay in these activities will directly impact the birthday celebration date.

Now, on the non-critical path, there are tasks that have more flexibility in their timing:

1. Gift Shopping
2. Balloon Arrangement

For example, Gift Shopping can be done at any time after the invitations are sent out, and Balloon Arrangement can be done at any time after the venue decoration is completed.

Let’s calculate float for one of the non-critical path tasks, Gift Shopping:

• Earliest Start (ES): 2 days (assuming invitations take 2 days to reach guests)
• Earliest Finish (EF): 7 days (assuming Gift Shopping takes 5 days)
• Latest Start (LS): 2 days (to keep the critical path on track)
• Latest Finish (LF): 12 days (to maintain the overall project deadline)

Total Float (TF): LF – EF = 12 – 7 = 5 days

This means Gift Shopping has a total float of 5 days, indicating you have flexibility in scheduling this task without affecting the overall celebration date. Similar calculations can be done for Balloon Arrangement and other non-critical path tasks. Understanding float in this context helps you manage your project timeline effectively, ensuring the critical activities are on track while allowing more flexibility for less time-sensitive tasks.

Why Float Matters?

• Schedule Flexibility: The term ‘float’ refers to the flexibility that the project schedule has. This is the number of days the end of a task can be pushed by without affecting the entire project delivery date. It is due to this flexibility that the organisational framework can allow for unforeseen issues, changes or delays while the course of the project is being executed.
• Critical Path Identification: The critical path is the order of activities that identifies the least amount of time for executing the project. The critical path having zero float means a delay in any of the tasks in the critical path will have a cumulative effect on the project completion date.
• Risk Management: These are the tasks that have either no float or the float is least and hence more prone to causing delays. Understanding float equips project managers with the necessary tools for risk assessment related to individual tasks in addition to prioritizing efforts to prevent slippage on absolutely critical tasks.
• Resource Optimization: Analysis of float is important in an efficient use of resources. Higher priority tasks with the biggest duration of the float can be scheduled more flexibly to achieve efficient resource utilization and minimize the order of resource conflicts.
• Early Warning System: The monitoring of variation in float values acts as a breaker for the project to move forward or to delay the project. This can be also interpreted as an early alarm if critical tasks float keeping in mind that they are close to their limits so some timely intervention is needed.
• Performance Measurement: Floats can be utilized as a reference that compares actual project performance against planned performance. The deviations of the actual float values show how the project is being realized correctly.
• Contingency Planning: Floating makes available all the information for contingency planning which can be good. The knowledge of available slack allows project managers to dedicate extra time for key activities or to adjust the method of accomplishment if unforeseen problems appear.

How to use float for better project management

Regardless of your preferred project management approach, whether it’s Agile, Kanban, critical path, PERT, waterfall, or any other framework, understanding total and free float is a valuable skill. It can significantly enhance resource management, internal and external scheduling, and the overall success of your project delivery. The beauty of float lies in its adaptability, making it applicable across various project management methodologies.

Conclusion

Understanding and effectively managing float are crucial elements in successful project management. Whether you’re using Agile, Kanban, or any other project management approach, float plays a significant role in resource optimization, scheduling flexibility, and overall project delivery.

FAQs on Float

Q. What are the Types of Float?

There are two types of float in project management, free float (FF) and total float (TF).

Q. What is the float on the critical path?

Any activity or task on the critical path has zero float. 

Q. Can a float be negative?

Float can be a positive or negative number.