It’s a tale project managers know well: trying to balance time, cost and scope throughout a project can feel precarious at best and impossible at worst. 

Scope changes, budget cuts and expedited deadlines are common challenges project managers face. However, the quality of the project can suffer if the three factors of time, cost and scope aren’t kept in balance. Project management is rarely an easy-going process, and the more moving parts introduced, the harder this balance is to maintain.

Luckily, there are methodologies that can help us navigate these challenges, such as the project management triangle. But what is this, and how can we use it? Let’s dive in.

  • What is the Project Management Triangle?
  • Pros of Using the Project Management Triangle
  • How to Use the Project Management Triangle Effectively
  • Choosing the Right Project Management Tool Based on Your Project Management Triangle

What is the Project Management Triangle?

The project management triangle (PMT), also known as an iron triangle, is a model that project managers can use to control the quality of a project’s outcome. The three points of the PMT represent the three variables that make up a project: time, cost and scope. 

These three variables are what determine the quality of a project. Yet, they are also often competing constraints. Every project manager has had the experience of trying to deliver a high-quality project with a budget that doesn’t match the scope, or a deadline so short that it’ll take every contractor on their books to get it done.

The PMT seeks to solve these issues as it dictates how changes to one variable will impact the other two. Simply, if one variable is changed, the other two must shift accordingly to keep the triangle from breaking. If one variable changes without a tradeoff between the other two to accommodate this, the triangle will break, resulting in the quality of the project deteriorating.

Let’s look at how the three points of the triangle interact.


Time refers not only to the literal amount of time a team has to complete a project, the hours available to be allotted to the project, but its phases, a team’s internal goals and timelines, and the time required for planning.


Similarly, cost doesn’t just refer to the financial value assigned to the project — its budget. Cost also covers any resources required to complete the project’s goal, including the team assigned to the project, external resources, tools, and physical resources, such as equipment and any facilities used. Ultimately, all resources have to be paid for with project costs and therefore hold financial value.


Simply, the scope is what the project intends to deliver. This relates to the scale of the deliverables, the quality and the attention to detail required. It is incredibly important to define project scope clearly before beginning any project.

How They Interact

Now that we’ve covered what each term refers to, let’s see how they directly impact each other. In the project management triangle, time, money and scope are all intrinsically linked; when one changes, so must the others. 

Firstly, the relationship between scope and the other two variables, time and cost, is directly proportional. That means when the scope increases, the other two must also increase in order to meet the requirements of a larger project. For example, if more deliverables are required, these will take more time to produce, and more money will be needed to pay for team members’ time.

The second type of relationship in the PMT is the inversely proportional relationship between time and cost. When the time or cost allocated to a project changes, the other factor must move in the opposite direction. So, when one decreases, the other must increase. For example, if a deadline is moved forward, extra budget will be required to facilitate the shorter timeline; comparatively, reduced budgets will mean deadlines need to be pushed back.

If these relationships aren’t respected in the face of change, the triangle will break, and the project’s quality will inevitably suffer.

Pros of Using the Project Management Triangle

Reading about the constraints of the project management triangle can feel restrictive. There is, after all, a reason the PMT is also known as the iron triangle. Yet, there are many benefits to respecting the rules dictated by the PMT. 


Depending on the type of company you work for and the project you’re managing, one of these constraints will always be less important than the other two.

The PMT makes it clear how the remainder of the project will be affected by this prioritization. There is nothing worse than making a change to budget, scope or timeline and not realizing the negative consequences until it’s too late and the quality of the work has already been affected.

Having these constraints outlined beforehand can help you always be one step ahead with planning, which leads us to our next benefit.


Agility is a quality most, if not all, project teams strive for. No matter your industry, changes and challenges are constantly thrown in your direction. As the project manager, it is your responsibility to field these before they negatively affect your team and project.

The PMT not only keeps you one step ahead but helps you make decisions about your project quickly and efficiently and aligns with the values outlined in the Agile Manifesto. As the triangle is iron and cannot be disregarded, no matter how tempting it may be, working to quickly change tact will always work in your favor.

Justification for Decisions

There will always be someone to answer to when a change is made to a project. Whether this is a team member, a key internal stakeholder or a client, people are entitled to challenge your decisions.

For example, if a stakeholder is disappointed to hear that the budget required to complete a project has been doubled due to them bringing the deadline forward, explaining the constraints of the PMT can help provide context to your decision to increase the costs. Or, if a resource manager doesn’t understand why you need more development time for the month, you can point them towards the growing project scope.

How to Use the Project Management Triangle Effectively

However, being aware of the triple-constraint project management triangle isn’t enough to guarantee successful, high-quality projects every time. You must take certain factors into account to ensure the effective running of a project.

Be Clear about the Project Expectations

A common pitfall of project management is not managing expectations clearly in the first instance. Failing to do so can result in unhappy stakeholders and clients, which reflects poorly on you, your team and the business.

By setting clear expectations of the project based on the costs available, time allocated, and the scope briefed, you can steer clear of complications later down the road. For example, you create a built-in contingency plan and budget that come into play in the event of an unexpected change in plans or delays caused by uncontrollable factors such as the weather. These should also clearly outline your action plan for minimizing the impact on cost and timelines should plans go awry and how this may impact the quality of the project.

Clarify the Priorities

As outlined previously, one point of the triangle will always be less important than the other two. This means that this is the point that will need to be flexible.

If the scope is non-negotiable and the timeline inflexible, then additional budget can be added to hire more people to work on the project. This will help get the work done on time and tackle issues without causing delays. If the timeline cannot be extended and more budget can’t be added, then the scope may need to be decreased to ensure what is delivered is of the best quality possible given the timelines and cost provided.

Review the Triangle Regularly

Reviewing the triangle regularly will ensure you can keep stakeholders and clients informed of how any changes will impact the overall running of the project. If you anticipate an issue, you can ensure everyone is aware of this even before it needs to be addressed.

Many factors can impact the running of a project, including sickness amongst the team, a key material running out or a national event shuttering production for a time. All in all, it is better to be prepared for the worst than to suffer from inaction.

Select the Right Project Management Tool

Depending on your working style, the type of project you’re managing and which points in your PMT take priority, there are several project management approaches that will work for you. This leads us on to our final piece of advice.

Choosing the Right Project Management Tool Based on Your Project Management Triangle

For Time Saving


A Scrum Board is a visual tool that helps teams working in Sprints track their work. To keep momentum and prevent breakdowns in communication from slowing down timelines, short, daily team stand-up meetings are favored over less-frequent review meetings.


A Kanban Board is an agile project management tool that aims to reduce the time spent focusing on work in progress stages by emphasizing visibility throughout the project. It doesn’t follow the concepts of sprints. Kanban boards are helpful for agile teams as they visualize work and maximize efficiency.

We break down the pros and cons of Scrum vs Kanban boards here.

For Cost-Saving


The lean project management method aims to get the most value from a project while minimizing wasted resources. To minimize the resource and budget required for a project, productivity is prioritized by avoiding bottlenecks. However, longer timelines or reduced scope are often necessary to keep the project within its lean budget.


Waterfall is a more traditional approach to project management as it follows a step-by-step sequence. It is important in waterfall projects that teams do not move backwards — instead, when you reach the end of a phase, you move on to the next, and once all phases have been completed, the project is closed. Instead of adjusting costs or deliverables, timelines should be flexible while working within this methodology.

For Scope-Management

If scope creep is a common issue you face, Forecast can help. With a wide range of project management tools and detailed reports available, you can quickly identify potential roadblocks that may delay timings, factors that are raising costs and deliverables that are skewing the balance of the iron triangle of project management.

To test out which project management tools work best for you and your team, you can sign up for a free 14-day trial of Forecast below.

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