You may think that the project life cycle and the product life cycle are similar; they are not. As a project manager, you should know the difference between these two concepts to align your business objectives with your project objectives.

Since a project produces a product and then ends and the product stays for a longer time, the product life cycle is bigger than the project life cycle.

On the PMP exam, you may see a few questions on this topic, so understand it well.

Project Life Cycle

A project life cycle is the sequence of phases that a project goes through from initiation to closure. Projects are undertaken to produce a product, service, or result, and after delivering the output the project ceases to exist and the project life cycle ends.

A project life cycle has many phases, and each phase consists of activities from these process groups: initiation, planning, executing, monitoring and controlling, and closing. The phases are generally sequential and can overlap.

In the initiation phase, you develop the project charter and identify stakeholders.

The project management plan will be developed during the planning phase and you build the actual product in the execution phase.

Monitoring and controlling activities happen throughout the project, although these processes can overlap or repeat.

In closing, you hand over the product to the client and close the project.

Project life cycles are not necessarily a part of the product life cycle. If the project’s output is a service or result, it will not be a part of the product life cycle.

The PMBOK Guide defines the project life cycles in four phases:

  1. Starting the project
  2. Organizing and preparing
  3. Carrying out the project work
  4. Closing the project

The following are some characteristics of a project life cycle:

  • Risks are higher when the project starts and decrease as the project progresses.
  • Staff requirements are low at the beginning of the project, maximum during the execution, and afterward, may decrease.
  • The cost of changes is lowest at the beginning of the project, and it starts increasing as the project moves further.
  • Stakeholder influence is higher at the beginning of the project, and it starts decreasing as the project moves further.
  • Most of the funds and time are spent during the execution phase.


Suppose you have a project to build a new motorcycle.

First, you identify the stakeholders and collect the requirements. Once the requirements are collected, you will develop a plan to build the motorcycle.

Then you start the real work of building the motorcycle.

Finally, you will hand over this product to your client, and the project will be closed.

Product Life Cycle

The product life cycle describes the stages a product passes through from conception to retirement.

The stages of the product life cycle are development, introduction, growth, maturity, and retirement. These phases are sequential and do not overlap. The project life cycle can be a part of one or more phases in the product life cycle.

In the development stage, you will generate the idea and create the product.

The introduction stage is for marketing the product and starting to sell the product to customers.

In the growth stage the sales increase.

In the maturity stage, the product is accepted, and sales are at their peak.

The last stage is the retirement stage. At this level, you will try to sell out all of your inventory and move on to the next product. This stage happens due to technical advancement or because your product is not selling enough to support its production cost.

Please note that not all products reach the final stage; some are discarded and others never expire.

Product life cycle phases have no duration limit, one phase can be longer than the others. For example, the Toyota Corolla and Camry are old products and are still in the growth or maturity stage, and I do not see them coming under the retirement stage any time soon.

A product life cycle can have many project life cycles. For example, the first project life cycle can be the development of the project, and the other, adding a function to the product.

In most cases, the project life cycle is a subset of the product life cycle because the product life cycle continues even after the project is completed.


Let’s consider the product life cycle for a new motorcycle that your company wants to launch.

The first step is idea generation. This includes a feasibility study, market research, and a business plan. Then you initiate a project to build this bike.

Once the motorcycle is ready, your project is complete and the project life cycle ends. However, the product life cycle continues. Now the next phase of the product life cycle begins, and that is selling and marketing the motorcycle.

You will provide after-sale support after selling, and finally, the retirement phase begins.

The retirement phase may include selling motorcycles at a discounted price.

During the product life cycle, if you add new functions to the product, you will create a new project for this process: for example, increasing the engine capacity of the motorcycle to support faster pickup.

The Differences Between the Project and Product Life Cycle

The following are a few differences between the project life cycle and the product life cycle:

  • A product life cycle can have single or multiple projects.
  • The product life cycle is longer than the project life cycle.
  • The project life cycle has a definite end while the product life cycle may not.
  • The map for the product life cycle is conceptual and depends on market conditions while projects have predictive and well-defined roadmaps.
  • The product life cycle phases do not overlap while the project phases may overlap.
  • Phases generally occur only once in the product life cycle while in the project life cycle phases may repeat.
  • Phases are sequential in the product life cycle, while in the project life cycle phases may or may not be sequential.


The project life cycle is a part of the product life cycle. The project life cycle is usually a subset of the product life cycle. The product life cycle starts from the inception of the idea and ends when the product is retired. The organization’s business model depends on the product cycle. A product life cycle includes the entire life of the product including updates and upgrades, however, products are upgraded with the help of a project.

Please share your role in the project or product life cycle in the comments section.