T-shirt size estimation

T-shirt size estimation swaps numbers for sizes: XS, S, M, L, XL and sometimes XXL. Instead of debating whether a story is 5 or 8 points, the team decides whether it is medium or large.

When to use it

• Long-term planning. When building a roadmap, precision doesn't help. Knowing one epic is an L and another is an S is enough to prioritize.
• Teams new to agile. Sizes are intuitive and avoid the temptation to convert points into hours.
• Conversations with the business. "This is an XL" says more to people outside the team than "this is 34 points".
• Triaging a large backlog. You can classify dozens of items quickly and only estimate in points what goes into the next sprints.

When to avoid it

T-shirt sizes don't add up. There is no "three M plus two S". If your team tracks velocity per sprint, you need numbers. A common approach is to agree on a planning-only conversion table, for example S = 2, M = 5, L = 8, and make clear it is approximate.

How to run a session

1. Pick a reference story for each size, or at least for M.
2. Present each item and ask everyone to vote secretly.
3. Reveal and discuss whenever votes differ by more than one size.
4. Record the chosen size and move on.

How StoryPoints calculates results

Sizes have no average. So for a T-shirt deck StoryPoints doesn't show an average: it shows the vote distribution, the agreement and the median by size order. If most people picked the same size, that becomes the suggestion. Otherwise the suggestion is the middle size.

To use it, create a room, open the options and pick T-shirt sizes as the deck. You can switch any time in the room settings.