Story Points Explained

What is a story point?

A story point is a single number that captures how big a task feels, taking into account the effort, the complexity, and the unknowns. It is a relative measure. A task worth 8 points is roughly twice as big as one worth 4. The points do not map to hours or days, and that is the whole idea.

Why not just estimate in hours?

Hours feel precise, but they are unreliable. The same task takes different people different amounts of time, and people are famously bad at guessing how long things will take. Relative sizing avoids the trap. Instead of arguing about whether something is a six hour job or an eight hour job, the team only has to agree on whether it is bigger or smaller than work they have already done.

How to estimate story points

1. Pick a reference task. Choose a small, well understood item everyone agrees on and give it a low number, like 2.
2. Compare everything to it. For each new task, ask whether it is about the same size, a bit bigger, or much bigger than your reference.
3. Use a simple scale. Most teams use Fibonacci numbers so the jumps get larger as tasks get less certain.
4. Vote together. Planning poker is the most common way to agree on a number as a team without anyone influencing the vote.

New to the voting part? Read our guide on what planning poker is.

Story points and velocity

Once you estimate in points, you can track how many your team finishes in a sprint. That number is your velocity. After a few sprints it settles into a range, and you can use it to forecast how much upcoming work you can take on. This is far more reliable than adding up hourly guesses, because it is based on what your team has actually delivered.