The Triple Constraint in Project Management: Time, Scope & Cost


The triple constraint of project management has been given many names – the Project Management Triangle, Iron Triangle, and Project Triangle – which should give you an idea of how important the triple constraint is when managing a project. If you’re managing a project, then you’re working with the Triple Constraint.

Therefore, it can be easily argued that the triple constraint might be the single most important concept in the history of project management. When used in combination with effective project management software, it can give you the ability to drive your projects to success.

What Is the Triple Constraint in Project Management?

So, what is the triple constraint? That’s easy, it’s a model of the constraints inherent in managing a project. Those constraints are threefold:

  1. Cost: The financial constraints of a project, also known as the project budget
  2. Scope: The tasks required to fulfill the project’s goals
  3. Time: The schedule for the project to reach completion

Basically, the triple constraint states that the success of the project is impacted by its costs, time, and scope. As a project manager, you can keep control of the triple constraint by balancing these three constraints through trade-offs. We’ll explain how these trade-offs work in the section below.

Get your free

Project Budget Template

Use this free Project Budget Template for Excel to manage your projects better.


While it’s true that the triple constraint is an important part of any successful project plan, it doesn’t determine success. Projects are made from many parts, more than the three that make up the triple constraint. That’s why some project management experts have added three more constraints to the model, to better reflect the most critical areas of a project. Here they are:

  • Quality: There are quality standards for every project, whether its final deliverable is a tangible or intangible product. Project managers need a quality management plan to control quality.
  • Risk: Risk is inherent to any project. That’s why project managers need to create a risk management plan to explain how project risks will be handled
  • Benefit: There are different types of benefit obtained from a project. Project managers must ensure that project stakeholders get the best financial benefit possible.

How Does the Triple Constraint Work?

As stated above, project managers can increase or reduce the cost, time and scope of a project with trade-offs to keep it on schedule and under budget. Let’s see how these project triangle trade-offs work with some examples.

  • Time and Scope: You can reduce your project scope to also reduce your project duration if you’re running behind schedule. In the opposite case, you can increase the length of your project timeline in case the project stakeholders come up with extra project activities.
  • Cost and Scope: By reducing the project scope, you’ll need to execute fewer tasks, which means lower costs. In the opposite case, a larger project scope means higher costs.
  • Cost and Time: In some projects, time and cost can be directly related. For example, the costs of renting equipment or labor are directly proportional to the time you need them for.

All these scenarios apply the triple constraint for managing the project, but there are many more possible trade-offs that can occur in a project, which also involve quality, risk and benefit.

By using a project management dashboard, a manager can keep sight of the project as it progresses. Metrics such as the schedule, cost and scope of the project are easy to track. With this information, a project manager can identify issues and adjust the triple constraint to prevent those issues from developing into problems.

Project Dashboard Template
Free dashboard template for Excel Download now

How to Manage the Triple Constraint

The triple constraint appears simple, but that’s only on the surface. Each of the three points of this triangle can be unpacked to reveal deeper meaning.


The financial commitment of the project is dependent on several variables. There are the resources involved, from materials to people, which all include costs.

There are also the fixed and variable costs inherent in any project, such as equipment or labor, which must be calculated. This can seriously come into play with the use of contract workers or outsourcing.

This is what project managers do to control costs:

  • Estimate the costs for all the tasks in the project scope
  • Create a project budget based on the estimated costs of the project
  • Use the project budget as a cost baseline, which is employed to control costs during project execution
  • Control all project costs to keep spending under the project budget
  • Adjust the project budget when necessary
Project budget template for managing cost in the triple constraint
Free project budget template. Download now


As mentioned, the project scope refers to all the project work required to complete the project. Managing that work is critical for project success. When managing scope it’s critical that you prioritize your tasks, enabling you to plan and assign resources effectively.

To manage scope, project managers:

  • Use a scope management plan to clearly define what project activities will be done
  • Share the scope management plan with all stakeholders, so everybody is on the same page
  • Use change orders to avoid scope creep and keep track of all changes made to the project scope
  • Manage stakeholder’s expectations to maintain the project scope
  • Use task management tools and techniques to keep track of all project activities in the scope

These scope management actions taken by project managers are all essential because the amount of time each task will require is critical to the cost and quality of the final product. This can have a great impact on schedule and cost, especially so if the project is on a large scale.

project scope template for managing scope in the triple constraint
Free project scope template. Download now


At its basic, the project schedule is the estimated timeline allotted to complete the project, or produce the final deliverable. Usually, this is figured out by first estimating the time that each project task will take.

A Work Breakdown Structure (WBS) is used to identify all the project activities. Then project managers can use different scheduling techniques such as the critical path method or PERT charts to determine the total duration of the project.

Here’s what project managers do to control the project schedule:

  • Use a Gantt chart to visualize the project schedule, define task sequences and monitor the duration of each task
  • Create policies, procedures and documentation for planning, executing and monitoring the project schedule
  • Allocate resources effectively using a resource schedule to avoid bottlenecks
  • Compare the schedule baseline to actual progress to determine if projects are on track
Gantt chart template for managing time in the triple constraint
Free Gantt chart template. Download now


Now that we’ve learned what most project managers do to control the triple constraint, let’s learn about the project management tools that you can use to help you with this process.

Controlling the Triple Constraint with ProjectManager

As mentioned at the top of the post, the triple constraint when used in conjunction with a project management software is the best way to control your project and lead it towards a successful end. ProjectManager is a cloud-based project management software with real-time data that gives project managers the power to manage each arm of the triple constraint: costs, time and scope.


ProjectManager helps you track your project costs to make sure you’re not overspending. You can create budgets, add project expenses and input hourly rates for all of your resources. The real-time dashboard tracks cost and five other metrics across your project and reports on them instantly in easy-to-read charts and graphs. This is an easy way to keep an eye on your costs and make sure you’re aligned with your budget. Now you can catch budget issues before they become a problem.


Your schedule can get away from you, but not with ProjectManager. When tasks are updated, they’re instantly reflected across the software. That means, your reports and dashboard are accurate and current. You can even watch the progress of individual tasks on the online Gantt chart, where the duration bar indicates how much progress has been made on the task.

Project timesheets are synced with the team’s tasks, which makes it easy for team members to select their task and just enter it. This brings their time into the timesheet, which can then be previewed and approved with a few clicks.

timesheet report for managing time in triple constraint


Scope is going to change throughout the project, and ProjectManager has the tools to stay flexible with those changes. There are multiple project views, so you can switch from the Gantt to the kanban view to get visibility into your workflow. Kanban cards, which represent tasks, are set by priority, which can change as the relevance of those tasks change.

A screenshot of the Kanban board project view

The great thing about kanban boards is that they’re set up to deliver tasks to team members only when the resources and capacity are there to complete them. As the scope of the project changes, the kanban board can quickly adjust.

If you notice teams are under- or overallocated, you can balance that out on the workload page. The workload page has color-coded charts that show at-a-glance who is overloaded with tasks and who is available. You can reallocate their work quickly and easily to keep the project within scope.

Related: Theory of Constraints: A Guide for Project Managers

The triple constraint will help you manage your project. Planning for the schedule, scope and cost of your project will help you achieve your goals and objectives. ProjectManager, a cloud-based project management software, gives you the tools to use this model effectively. See how our real-time dashboards & interactive Gantt charts can help you by taking this free 30-day trial.