Modified Fibonacci with Sprint Poker
The start card is set to the modified Fibonacci deck: 0, ½, 1, 2, 3, 5, 8, 13, 20, 40 and 100, plus ? and coffee. The room comes with a mixed backlog, from a half-point config change to a 40-sized epic, so the team can see where the round numbers at the top of the scale earn their place.
- Type your name and press Enter. The room opens with the modified Fibonacci deck and six stories ranging from tiny to epic.
- Share the link. Up to 5 teammates vote in a free room; stakeholders can join as spectators and follow along without voting.
- Start with the smallest item. If most people reach for ½, that is the value of a trivial change; if not, agree on what 1 means for your team before going further.
- Vote, then press R. With values above 13 the reveal mostly tells you whether the item needs splitting; a mix of 20, 40 and 100 means nobody understands it yet.
- Set the final value and press N. When you are done, copy the session summary as text, or with Pro export it as CSV from the room menu.
What to know
The modified scale keeps the Fibonacci values up to 13 and then switches to 20, 40 and 100. The round numbers are deliberate: at that size nobody can tell a 34 from a 40, and using numbers that look precise invites false arguments. It is the deck printed on the planning poker cards popularised by Mike Cohn, and many teams adopted it from there.
The ½ card is for work that is real but small: a config flag, a copy fix, a dependency bump with no code changes. It stops those items being rounded up to 1 and inflating velocity, and it gives the team a way to say "trivial" without pretending it costs nothing. If your team never plays it, it does no harm to keep it in the deck.
Treat 20, 40 and 100 as sizes for epics and roadmap items, not sprint commitments. A common rule is that anything above 13 must be split before it enters a sprint. In refinement, the reveal is still useful: if one person plays 13 and another plays 100 on the same epic, they are picturing different scopes, and the outlier prompt names who to ask.
Because ½ counts as 0.5, the average and median after each reveal are real numbers, so a round of ½, 1, 1, 2 shows a median of 1. If you also use the Calibration view (Pro) after the sprint, values from this deck are compared with the cycle time of the work, so you can see whether your 20s really behave like four times your 5s.
Updated · Cosmovex
Questions
What is the difference between Fibonacci and modified Fibonacci?
They are the same up to 13. Above that, the classic sequence continues 21, 34, 55, 89, while the modified one uses 20, 40 and 100, and it adds a ½ card for very small work.
Why 20, 40 and 100 instead of 21, 34 and 55?
Large estimates are rough by nature, and round numbers say so. They also discourage debates over a few points when the uncertainty is much larger than the difference.
How is ½ counted in the stats?
As 0.5. Average, median, minimum, maximum and spread all include it, so a story voted ½, ½ and 1 gets a median of 0.5.
Can I add a 0.25 or an infinity card?
Yes, with a custom deck, which is part of Pro: the facilitator types the cards in the room settings, separated by commas, up to 20 cards of up to 8 characters each. The modified Fibonacci deck itself is free.
Does the modified deck work with the Calibration view?
Yes. Calibration, a Pro feature, matches issue keys from your session with an actuals CSV and plots each final estimate against the real cycle time. You can preview it free with sample sprints.
The free plan covers everything on this page. Sprint Poker Pro ($29, paid once) is described on the Sprint Poker page.
