The Iron Triangle Of Project Management

Written by Kainat Abdul Wahab

Kainat Abdul Wahab is the Head of PMO Department at KUWAITNET. She lives by the ideology of "Simple Living, High Thinking."

Why the name “Iron Triangle”?

The three main constraints (aspects) of any project are:

  • Scope

  • Budget

  • Time

The constraints were considered as “iron” since a project manager could not change one constraint without affecting the other. The above constraints directly affect the fourth and the most crucial aspect  “quality” of the project delivery. If you change any one of the constraints of the iron triangle, the others are affected. The aim of the iron triangle was to provide project managers with the required information for making the trade-offs that help in quality product delivery.


The triangle is also known as “Triple Constraints” or the “Balance-Triangle” denoting the importance of balance between the three aspects. These three constraints are also known as Competing Constraints. If the 3 are not in proportion with each other, you can see how the triangle will look like.

Why follow the Iron Triangle?

The main motive for following the triangle is to ensure quality improvements. Regardless of the different approaches used when managing a project there is no right and wrong way. The project managers should be well aware of the relationship between different constraints.  The iron triangle model helps the project manager know how different constraints affect the quality of the project outcome. Knowing about the constraints can help in making more effective decision. It will allow the project manager to more efficiently allocate the resources that result in optimal project outcome satisfying the requirements of the customer. When you’re managing a project, some variables can change. Others can’t.  The Triple constraints gives you a firm sense of what can and can’t be adjusted throughout the course of the project.

For example, if you’re running behind schedule, you can work to reduce the features of the project. That’s reducing scope. Then you can dedicate more resources to moving the schedule ahead. That’s increasing cost. You can also, if possible, change the due date to give you more time. All these scenarios are applying the Triple Constraint for managing the project.

The Man running the Show

Project manager is the person trading between these constraints, trying to balance all the constraints while managing the customer expectations and most importantly the Quality.


Basically, the triple constraints is really a balancing act. It’s like juggling; it looks easy until you try it. And just like a juggling, it takes practice. For a project manager, that means taking the time to understand the Triple Constraint as it applies to the project and doing your due diligence beforehand so that if you must adjust, you’re doing so with utmost calculation.

Planning well for the schedule, scope, and cost of your project will help you achieve your goals and objectives and hence the quality. So next time when a Project Manager says, “Sorry, that’s out of scope.” or “Sorry, This will deviate the project from the schedule.” you know what he/she is talking about.

Cost, Details, ProjectManagement, ProjectPlan, QualityManagement, Scope,