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What is the Project Management Triangle?

Published By Team AdaptiveWork

What is the Project Management Triangle?

The project management triangle defines the basic constraints that a project operates within, namely:

  • Cost
  • Time
  • Scope

The triangle model demonstrates how one element cannot be altered without affecting the other constraints. For example, a broadening of the scope of a project will most likely lead to increases in time and cost, similarly, a tightening of the proposed deadline will necessitate a narrowing of the scope or an increase in costs.

project management triangle

As it is such an intrinsic element of project management it’s no surprise that many people find themselves asking, “what is the project management triangle?” As ever we’re here to help and supply answers about all the most important details of project management.

The project management triangle

The project management triangle is also known as the Project Triangle, Iron Triangle or Triple Constraint. To understand this model of constraints even further it is necessary to break down its constituent parts.


Understanding the costs and limits of the proposed budget for a project are vital for any project manager. Cost estimates are guidelines that can be changed but project success generally depends on these predictions being adhered to. If a project is subject to many changes in costs, this can greatly affect the proposed project path and the chances of the project being delivered within its time and scope. The costs of a project can be altered by many factors, such as:

  • Suppliers increasing prices
  • Foreign exchange fluctuations for international projects
  • A broadened project scope requiring additional deliverables
  • Staff changes that incur recruitment costs
  • Costs for implementing new technologies

As all projects operate under a cost constraint, changes to the costs naturally impact the possibility of the project meeting its expectations with regards to Time and Scope.

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Each task that makes up a project takes a set amount of time. By adding these together, including the inter-related or dependent task strands, a project manager can establish a project timeline, which will estimate when certain milestones will be reached and specific deliverables handed over. While sticking to the predetermined schedule that has been signed off on is recommended for any PM, circumstances often mean that this has to be altered. Reasons for this can be:

  • Client requesting additional deliverables]
  • Delays in supply from vendors
  • Technology problems (i.e. viruses, server breakdowns)
  • Underestimation of task duration

Time constraints are very often over-run, and force changes to either Scope or Cost or both. For example, if a website was due to be delivered on the 15th of January, but the client decides they want to have it live before Christmas, then either more money has to be spent (on contractors or overtime) or the scope would have to be narrowed, e.g. to have less pages or features on the site.


The scope of a project is an integral element of the Project Management Triangle as it refers to the final result that is due to be delivered. It is important for project managers to be able to balance the scope of a project in terms of time and cost, by giving accurate predictions so that clients and other stakeholders understand how changes to scope will affect the other elements and similarly how adjustments to the budget or deadline will put pressure on achieving the desired scope.

To successfully balance the Project Management Triangle, transparency and visibility of the three constraints are vital. By using project management software such as Planview AdaptiveWork you can maintain full knowledge of how each of the constraints are performing and identify future risks.

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Written by Team AdaptiveWork