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

Key takeaways

• The triple constraints of project management are time, scope, and cost, represented by a triangle with one constraint on each side, each of which project managers must balance to keep the project on track.

• The importance of the triple constraints of project management lies in their interdependence: when one constraint changes, the others typically must adjust.

• You may also hear professionals refer to it as the iron triangle in project management, with time referring to the project’s duration, scope defining the project’s deliverables, and cost representing the project’s budget.

Managing project constraints requires clear communication with clients and stakeholders to thoroughly understand the project’s non-negotiables and other key considerations throughout the project. Continue reading to learn more about the triple constraints in project management, how they interrelate, and tips to manage them effectively. Afterward, consider enrolling in the Google Project Management Professional Certificate to learn the foundations of Agile project management with a focus on implementing Scrum events. You’ll also have opportunities to practice stakeholder management and strategic communication through real-world scenarios.

What are the triple constraints of project management?

The triple constraint triangle of project management, sometimes called the iron triangle, is a model often visualized as three equal sides: time, scope, and cost. These three factors are the constraints that project managers juggle during project planning, execution, and delivery to keep the 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 estimate how long a project will take and ensure they have enough people working on the job to complete it on time.

Scope

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

Cost

The cost is the project budget. 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 encounters a constraint, the project manager uses the triple constraint model to compensate and bring the project back into line. Time, scope, and cost interlink in such a way that if one shifts, the others must as well.

How the triple constraints of project management are linked

The three constraints of project management often share an interdependent relationship in which increasing or decreasing one or more may affect the others. They relate primarily in two distinct ways, with scope and both time and cost sharing a directly proportional relationship, in which an increase in scope typically requires an increase in budget and time. Additionally, time and cost are inversely proportional: reducing one requires increasing the other. Understanding the impact of each constraint can help you prepare for any adjustments you may need to keep projects on track.

Over budget

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

Shifting scope means reducing the expected deliverables and completing less work, which requires less time and, therefore, costs less. Another option is to find another way to cut time, such as completing the work with less labor or fewer 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 as the project progresses without following proper procedures, such as submitting change requests. When the scope expands, a project manager can adjust time and cost to compensate.

If the scope expands, the project manager can request a larger budget to increase the labor, tools, and materials needed to complete the project. With enough additional funding, the project manager might avoid pushing the schedule back. Otherwise, it’s likely a bigger project will require a longer timeline to complete.

Over schedule

When a project runs over schedule, a project manager might shift cost or scope to get the project done on time.

By adding money to the project, the project manager could access better tools or pay the labor costs of a bigger workforce to get the project done. Alternatively, they could meet with the client to reduce the project's scope.

What are some examples of project constraints?

Triple constraints of project management can affect projects across industries. Reviewing a few of the concepts and the interplay between them in real-world examples can help you better understand how project constraints can 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 prioritize 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 labor hours and resources, or they will have to remove other materials to make room for the new additions.

Software start-up goes over budget

A start-up aims to launch its flagship software in 12 weeks, and the development team runs into technical challenges that were unanticipated when they created the budget, requiring them to bring on an additional developer to solve the issue. The software project manager and the client had a contingency plan in place that allowed additional time for the project since the scope was nonnegotiable.

How to manage the triple constraints of project management

Once you understand the importance of the triple constraints on a project, the next step is to learn the best practices for managing them. Review some tips to help you use the triple constraint triangle as a tool for success:

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

• Be aware of other factors: In some products, factors like the quality of the final product will also be an important constraint. Be flexible with a more adaptable model of project constraints for your project needs.

• Communicate with stakeholders: Managing projects takes skill, and clear communication at every step helps project managers set expectations and secure the buy-in they need from stakeholders.

How to get started in project management

The Project Management Institute offers the Project Management Professional (PMP) certification, a globally recognized credential that demonstrates your skills.

To qualify for the exam, you can either complete your high school diploma and gain 60 months of experience leading projects, earn an associate degree and complete 48 months of relevant project management experience, or earn a four-year degree and 36 months of project management experience. In either track, you’ll need to have the experience within the past 10 years and gain an additional 35 hours of project management training, which can be met with the Certified Associate in Project Management (CAPM) credential, the PMP exam prep course, or an instructor-led PMP course, among other methods.

After completing the requirements, you’ll be eligible to take the PMP exam and earn your certification.

Read more: Project Manager Career Path: From Entry-Level to VP

Benefits of becoming a certified project manager

Getting certified demonstrates that you have project leadership expertise that goes beyond industry or methodology. The advantages of getting project management certification include:

• Higher salary: The Project Management Institute reports that certified PMPs earn 17 percent more than their non-certified counterparts, with a median salary of $135,000 [1].

• Community: The Project Management Institute is a global organization with 80,000 members and 1.7 million certification holders worldwide, creating opportunities for professional networking and potential mentorship [2, 1].

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

Check out our free resources on project management

Join Career Chat on LinkedIn to stay current with the latest trends in project management. Learn more about project management with our other free digital resources:

• Read our Career Chat issue: Project Management Tools: Uses + Considerations

• Learn terminology: Project Management Terms and Definitions

• Watch on YouTube: Scrum Master vs. Project Manager: Which Role Fits You?

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