T-shirt sizes aren’t what you think: How to use t-shirt sizing for project estimation

What if we told you t-shirt sizes weren’t just for, well, clothing? T-shirt sizing also refers to a powerful project estimation tool for capacity planning. Two parts useful, one part whimsical, this tool provides clarity about exactly what’s on each team member’s plate.

Any time you think of implementing a new practice on your team, you also have to think about the complexity: How much work will this take to set up? Is this a practice my team will easily understand, and benefit from? 

With t-shirt sizing, you can skip these concerns. Everyone has worn a t-shirt, so it’s easy for team members to immediately understand the difference between an Extra Small t-shirt and a Large one. Applying these sizes to team initiatives is a great way to gauge effort for each task—without doing a bunch of complicated math. Here’s how.

What is t-shirt sizing? 

T-shirt sizing is a project estimation and capacity planning tool that helps you track how much time or effort an initiative will take. To do this, you assign each project or task a t-shirt size—from Extra Small to XXL—to represent that task’s relative effort. Depending on how you choose to use this tool, a t-shirt size can represent task scope, effort, complexity, work hours, time estimates—or all of the above.

T-shirt sizing is a helpful tool for your entire team: 

• Project leads can quickly gauge team capacity. 

• Individual contributors can communicate their bandwidth and priorities clearly.

• Team members can understand who’s doing what by when.

This technique is often used by engineering and software development teams, but any team can benefit from it—in fact, we use t-shirt sizing here at Asana for content projects (this article, for example, is a Medium).

How to use t-shirt sizing for Agile projects

Agile and Scrum teams initially popularized t-shirt sizing as a way to measure story points. Story points—also known as planning poker—are a way to estimate effort or relative size of work during sprint planning. Typically, story points are assigned to requests or work in a product backlog. When the Scrum master begins the next sprint cycle, they pull tasks from the backlog until they hit a certain number of story points. That way, the Scrum team ensures they have enough to work on during the sprint—without biting off more than they can chew.

T-shirt sizing for Scrum teams is a form of relative estimation. This is an alternative to the more traditional, numerical story points estimation technique. Unlike numbers, relative estimating allows team members to think in more dimensions—numbers are often associated with time, but t-shirt sizes can represent more complex ideas, including time, effort, and complexity.

6 steps to using t-shirt sizing for project estimation

To use t-shirt sizing effectively, it’s important to establish up front what each t-shirt size represents and where team members should clarify relative sizing. 

1. Start by deciding on your sizes

Before you introduce t-shirt sizing to your team, decide on the sizes you want to use. Avoid using too many sizes so team members aren’t confused. If you’re just getting started, stick to Small, Medium, Large, and Extra Large. If your projects vary widely in scope, use Extra Small or Extra, Extra Large as well. 

2. Align on what each size represents

T-shirt sizing only works if everyone understands what each size represents. So as you introduce this project estimation practice to your team, make sure everyone is on the same page about it. It’s helpful to provide common examples of a Small vs. Large project. For example, on the content team at Asana, an article like this one is a Medium. Alternatively, a cross-functional content initiative with multiple pieces and a variety of project stakeholders is a Large or, in some cases, even an Extra Large. 

When you do this, also clarify what a t-shirt size represents. Does the size represent effort? Complexity? Time? Often, a t-shirt size represents all of the above, but clarifying what you are and aren’t tracking with t-shirt sizes is a helpful way to get everyone on the same page.

3. Decide who assigns t-shirt sizes

Depending on your team structure, consider limiting who can assign t-shirt sizes or opening it up for the entire team. Here are a few common ways to limit who can assign t-shirt sizes:

• For product backlog projects, the product owner assigns t-shirt sizes, because they’re closest to the work. 

• For Agile teams running Scrum, the Scrum master reviews t-shirt sizes, which were previously assigned by a product owner, before a sprint. 

• For general project teams, each team member sets their own t-shirt sizes, based on the team’s understanding of what each size of work represents.

4. Assign t-shirt sizes to each initiative

If you’re just starting out, you may have to retroactively assign t-shirt sizes to work in flight. But, moving forward, each piece of work should have an associated t-shirt size when it’s assigned, so you and the team member both understand how much effort that work represents.

5. Track t-shirt sizes using a work management tool

Having t-shirt sizes associated with work is good—but seeing that information in a clear, centrally accessible tool is much, much better. Make sure your team tracks t-shirt sizes in a shared work management tool, like Asana. That way, you—and all other team members—get at-a-glance insight into each team member’s current workload. 

6. Use t-shirt sizing to gauge workload

Once each task has an associated t-shirt size, you also have built-in workload tracking for your team. Use a work management tool, like Asana, to gauge associated effort and get a sense of how much work each team member has on their plate. By tracking this work, you can ensure team members aren’t getting burnt out. 

T-shirt sizing estimation examples

Here’s an example of a sprint planning project, using t-shirt sizing in place of traditional story points:

Engineers aren’t the only ones who benefit from t-shirt sizing. Here’s another example of a content calendar with associated t-shirt sizes for each piece of content:

The benefits of t-shirt sizing 

Though simple to use, t-shirt sizing is a powerful way to simplify estimation lead time—especially for non-engineering teams. With t-shirt sizing as a shorthand for capacity and effort, team members spend less time thinking about how many hours a task will take and more time getting high-impact work done. 

When you track t-shirt sizing in a centralized tool, everyone not only sees who’s doing what by when, but also how much they’re doing at any given point. Plus, t-shirt sizing is a great stepping stone to workload management and capacity planning. With workload management, you can effectively distribute work across your team to reduce burnout. With proactive workload management, you can also prevent team members from feeling overworked in the first place.

Common t-shirt sizing pitfalls—and how to avoid them

T-shirt sizing is powerful, and easy to set up, but there are a few things to watch out for as you implement this project estimation methodology: 

Problem: T-shirt sizing is subjective

Solution: Establish sizes for common projects so everyone is on the same page.

To prevent this problem, make sure you provide context for t-shirt sizes when you first roll them out. That way, you avoid the subjective component and ensure everyone on your team clearly understands the difference between an Extra Small, Small, and Medium t-shirt task. 

Problem: The difference between different sizes is unclear

Solution: Stick to fewer sizes.

If your team can’t understand the nuances between multiple sizes, reduce the number of sizes they’re choosing from. Stick to S, M, L, and XL—or remove XL all together and stick to S, M, and L. You can always add more sizes if necessary.

Problem: Tracking an initiative’s associated t-shirt size is difficult

Solution: Use a work management tool. 

There are two huge benefits to t-shirt sizing: capacity planning and workload visibility. In both cases, you need a way to access everyone’s work in a centralized tool in order to reap the benefits. That’s where work management tools come in. 

Work management tools provide the clarity teams need in order to hit their goals faster. With these tools, you can coordinate people and work across your team, and ensure everyone has the information they need to accomplish their highest-impact work. To learn more, read our introduction to work management. 

Try it on, see if it fits

With t-shirt sizing, you can assign rough estimates to virtually any kind of work. This is also a way to build workload management practices on your team, which helps you effectively gauge team member capacity and fight overwork. To use t-shirt sizing most effectively, make sure you’re tracking your work in a centrally accessible tool, like Asana.