T-shirt sizing
T-shirt sizing is a relative-estimation technique that assigns work items to size buckets — XS, S, M, L, XL — instead of point or hour estimates. The lack of numeric precision is the point: it surfaces relative magnitude differences faster than story-point estimation while sidestepping the false-precision trap of hour-based estimates.
T-shirt sizing is most useful at the very-early stages of a project (epic-level or quarterly roadmap) where teams need to communicate 'this work is bigger than that work' without committing to numbers that will later be cited as deadlines. Conversion to capacity planning happens implicitly: an XL might represent multiple sprints; an XS might fit inside one. Some teams use t-shirt sizes at the epic level and translate to story points (Fibonacci 1, 2, 3, 5, 8, 13) at the story level. The shared cognitive cost of agreement is much lower for t-shirt sizes — you almost never argue about whether something is an L versus an XL the way teams argue about whether a story is 5 versus 8 points.
Related terms
- Relative estimation
Relative estimation sizes work items against each other (this story is twice as big as that one) rather than in absolute units (this story will take 6 hours).
- Story points
A story-point estimate is a unit-less measure of relative effort assigned to a user story.
- Planning poker
Planning poker is a consensus-based estimation technique where each engineer privately picks a Fibonacci card (1, 2, 3, 5, 8, 13, …) for a story, then reveals simultaneously.