The Triple Constraints of Project Management: Time, Scope, and Cost

Three main factors determine a project's feasibility: time, or how long it will take; cost, or how much money will be spent on it; and scope, the deliverable at the end of the project. Increasing or decreasing one will affect the others. The project manager must balance these constraints to deliver on a project successfully.

What is the triple constraint triangle?

The triple constraint triangle of project management is the visualisation of a triangle, with sides formed by time, scope, and cost. These three factors are the constraints that project managers juggle to keep a project running as expected. 

Time

Time is how long the project will take. It’s important for project managers to make sure the team finishes the project before a deadline. A project manager must figure out how long a project will take and ensure enough people working on the job to complete it in time. 

Scope

The scope of the work refers to the project's deliverables or the result. It should be clearly defined and monitored throughout the project before beginning work. Scope creep, or the project getting bigger or changing without proper protocol, can throw the constraint triangle off balance. 

Cost

The cost is the budget of the project. Clients and project managers agree on a budget before beginning the project, and keeping a project on budget will be one measure of success. 

When a project is met with one of the constraints, the project manager uses the triple constraint model to compensate and bring the project back into line. Time, scope, and cost interlink so that if one shifts, the others must also. Let’s look at how these three factors relate to one another. 

The link between time, scope, and cost 

When one of the triple constraints goes off track, the project manager may need to adjust. The following offers some everyday ways a project manager might adjust to keep the project on track. 

Over budget

When a project exceeds budget, it’s on track to spend more money than the client agreed to pay. Budget is the cost constraint, meaning scope or time must shift to accommodate. 

Shifting scope means lowering the expected deliverables and completing less work, which also requires less time and costs less. Another option is to find another way to cut time, such as completing the work with less labour or tools. In that case, the scope would remain the same, and only time and cost would adjust. 

Scope creep

Scope creep happens when the expected deliverables grow larger and larger as the project progresses without following proper procedures, such as making change requests. When the scope expands, a project manager can adjust time and cost to compensate. 

If the scope expands, the project manager can ask for more budget to increase the labour, tools, and materials needed to complete the project. With enough additional funding, the project manager might avoid pushing the schedule back. Otherwise, a bigger project will likely require a longer timeline to complete. 

Over schedule

When a project runs over schedule, a project manager might shift costs or scope to finish the project on time. 

By adding money to the project, the project manager could access better tools or pay the labour costs of a bigger workforce to complete the project. Alternatively, they could meet with the client to reduce the project scope. 

Examples of the triple constraints of project management

To understand these concepts in the real world, let’s examine some examples of triple constraints and how they affect project management:

Construction deadline

A construction company is building a new office complex for a client. The client requested to move into the building a month earlier than originally scheduled. The project manager might accommodate this request by increasing the budget and bringing in a larger crew to finish the project faster. Or, they might prioritise certain areas of the building to finish early so the client can move in while construction continues, which would be an example of rearranging the scope to fit the new requirements. 

Marketing scope creep

A marketing team is preparing a package of marketing materials for a client ahead of a new product launch. The client requests five additional pages of material. The client doesn’t want to push back the product launch, so the time constraint has to remain the same. The project manager and the client will have to agree to either increase the budget and use more labour hours and resources or they will have to remove other materials to make room for the new additions.

How to manage the triple constraint

Once you understand the importance of the triple constraints on a project, the next step is learning the best management practices. Use the following three tips to use the triple constraint triangle as a tool for success: 

• Understand non-negotiables: Some constraints will be more flexible than others, depending on the project and client. For example, budget might be negotiable while time and scope are not. Understanding what’s more important to your client makes you more likely to deliver on their expectations successfully. 

• Be aware of other factors: In some products, factors like the quality of the final product will also be important constraints. Be flexible and use a more adapted model of project constraints for whatever your project needs are. 

• Communicate with stakeholders: Project management requires skill, and clear communication at every step helps project managers manage expectations and get the buy-in they need from stakeholders.  

How to get started in project management

The Project Management Institute offers a Project Management Professional (PMP) certification for you as a project manager to demonstrate your skills with globally recognised credentials.

To qualify for the exam, you can either complete your secondary school certificate and gain 60 months of experience leading projects or a four-year degree and gain 36 months of project management experience. In either track, you’ll need to have the experience within the past eight years and gain an additional 35 hours of project management training.

After completing the requirements, you can take the PMP exam and earn your certification. 

Benefits of becoming a certified project manager

Earning a certification provides demonstrable proof of your knowledge and abilities. Additional advantages of getting project management certification include:

• Higher salary: The Project Management Institute reports that certified PMPs made 16 percent more money than their non-certified counterparts [1].

• Community: The Project Management Institute is a global organisation with over 600,000 certification holders worldwide, creating opportunities for professional networking and potential mentorship [2]. 

• Confidence: Earning your certification can help you feel confident in your skills and secure in your understanding of industry best practices. 

Get started on Coursera 

Understanding the Triple Constraint Triangle is an integral part of working in project management and can support you in starting your project management career. On Coursera, you’ll find resources to help develop foundational and advanced knowledge to begin or further your career as a project manager. Consider Google Project Management: Professional Certificate offered by Google Career Certificates to help you develop your project planning, change management, and risk management skills.

This beginner-friendly course takes approximately six months to complete, although you could also take any courses individually.