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How to Estimate the Size of a Project

When asked how to size any project, project executives often use the Potter Stewart standard – “I know it when I see it.” Project managers and sponsors, especially the seasoned lot, may be dodging the issue. For them, sizing a project may be an undertaking that they do so well and so instinctively that when they try to communicate it, they fail. The subject suddenly becomes inexplicable when one attempts to articulate it.

Nonetheless, this exposes the bad faith common in the PM landscape, allowing the expert PM to hide behind the sagely prestige of the professional and leaving the neophyte confused or mystified. While it may be true that these project managers are most of the time on point in creating a workable estimate, it is still important to discover how they do it, even if they themselves can’t explain it.

So by which yardstick do we measure the size of a project? Regardless of the duration, required budget, complexity, and possible impact of a project, sizing it up is no easy task. Here we give you a brief guide on how to estimate the size of your next project:


If there’s a lack of clearly defined parameters, it’s not that bad to give project estimates at face value. If what you only have is a project request, be ready to ask the following questions. The elicited details will likely put you in a better place to determine the project’s size.

  • What is the goal of the project?
  • How much budget is allotted for the project?
  • How much human resources do you need?
  • Do you need to buy new tools and equipment?
  • What is the timeline for the project?
  • Do you have subject matter experts who can help expedite the project management processes?


In the absence of a project sizing guide in your organization, historical data can save the day! Previous projects, when documented, can serve you well in creating better estimates. Are month-long projects considered small? Are projects requiring over 1 million pesos considered medium? Sure, every project is unique, but historical data can at least provide you a benchmark of how projects are estimated at least within your organization. You are not left with a blank slate.


In project sizing, there’s always that one dimension, which the organization places heavy emphasis on, that ultimately determine the project’s size. Is yours finicky about project costs? Then you should estimate based on your project’s required budget. Does your organization have low risk appetite? Maybe you should categorize based on the level of risk associated with doing a project? Likewise, other organizations put greater considerations on timeline and human and physical resources than financial costs, so be sure to operate within their limits.

Project sizing is a skill that can be honed by any project manager through time. The more projects you undertake, the better you get at giving an estimate that will enable you and the project board to agree on its size. Take your time and enjoy the challenge and practice!