Planning Poker vs. T-Shirt Sizing

Both are relative-estimation techniques - see our Story Points Explained page for why "relative" matters. The difference is the scale teams vote with.

Planning Poker (numbered cards)

Teams vote using a Fibonacci-like deck - 1, 2, 3, 5, 8, 13, 21. It's precise enough to distinguish between a handful of similarly-sized stories in the same sprint, and the growing gaps between numbers naturally discourage false precision on bigger, less-understood work.

T-shirt sizing (XS, S, M, L, XL)

Teams vote using size labels instead of numbers. It's faster to reach for and feels less intimidating to newer team members who find raw numbers overly clinical - "this feels like a Medium" is an easier first guess than picking between an 8 and a 13. The tradeoff is resolution: once a backlog has more than five or six sizes' worth of variety, several genuinely different stories end up lumped into the same "L," which numbered decks distinguish more easily.

When to use which

T-shirt sizing tends to work well for very early, coarse triage - roadmap-level "is this roughly a quarter of work or a week," before anyone's dug into details. Numbered Planning Poker fits better once a team is estimating actual sprint-ready backlog items and needs enough resolution to plan capacity sensibly.

Some teams do both: T-shirt sizes for rough roadmap planning, then numbered Planning Poker once a story is close enough to being worked on that the team wants a tighter estimate.

Where Fibopoker fits

Fibopoker runs numbered, Fibonacci-style Planning Poker - it doesn't currently offer T-shirt sizing as a deck option. If your team estimates with numbers, it's a good fit; if you're specifically after T-shirt sizes, look for a tool that supports that deck type.