T Shirt Sizing: Agile Estimation & Capacity Planning

What if we told you t-shirt sizes weren't just for clothing? T-shirt sizing is also a powerful project estimation tool, providing clarity about exactly what's on each team member's plate. When implementing a new practice, you naturally ask: How much work will this take to set up? Will my team easily understand it?

With t-shirt sizing, you can skip these concerns. Everyone intuitively understands the difference between an Extra Small and a Large t-shirt, and applying these sizes to team initiatives is a great way to gauge effort without complicated math.

What is t-shirt sizing?

T-shirt sizing is an Agile estimation technique that uses familiar clothing sizes (XS, S, M, L, XL, XXL) to represent the relative effort of a task or project. Instead of assigning exact hours, teams use these intuitive sizes to quickly gauge scope, complexity, and capacity.

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 are a way to estimate effort or the relative size of work during sprint planning, and they're typically assigned to requests or work in a product backlog.

When the Scrum master begins the next sprint cycle, they pull tasks from the sprint backlog until they hit a certain number of story points. This helps the team take on enough work 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.

When to use t-shirt sizing vs. story points

While both t-shirt sizing and story points help Agile teams estimate work, they serve different purposes. Think of t-shirt sizing as a tool for quick, high-level planning when you need a general sense of effort without getting stuck on exact numbers.

Story points offer more precision. Teams typically use them during sprint planning to assign numerical values to tasks, which helps create more detailed and predictable sprints.

Pro tip: Many teams use both together, t-shirt sizes for high-level planning, then story points as work moves closer to execution.

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. As you introduce this practice to your team, make sure everyone is aligned by providing common examples of each size.

For example, on the content team at Asana:

• Medium: A standalone article like this one

• Large: A cross-functional content initiative with multiple pieces and a variety of project stakeholders

• Extra Large: A major campaign spanning multiple teams and deliverables

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 the t-shirt sizes previously assigned by the product owner before a sprint.

• For general project teams, each team member sets their own t-shirt size based on the team's understanding of what each size 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. Moving forward, each piece of work should have an associated t-shirt size when it's assigned. This ensures 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 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 is assigned a 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 can see who's doing what by when and how much they're doing at any given point. T-shirt sizing also serves as a stepping stone to broader workload management practices:

• Distribute work evenly: Spot imbalances before they lead to burnout

• Prevent overwork: Identify when team members are taking on too much

• Plan capacity: Make informed decisions about what your team can realistically take on

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 altogether 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 centralized tool to access everyone's work to reap the benefits. That's where work management tools come in.

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

Make t-shirt sizing work for your team

T-shirt sizing offers a simple, intuitive way to estimate work and manage your team's capacity. By bringing these estimates into a central tool, you can give everyone clarity on what's being worked on and prevent burnout before it starts. Ready to see how it fits your team? Get started with Asana today.

Frequently asked questions about t-shirt sizing