Story Point Converter
Instantly convert between Fibonacci story points, T-shirt sizes, ideal days, and hours. A quick reference for any agile team.
Interactive Converter
Select a scale and value to see its equivalent across all other scales.
Full Reference Table
Click any row to highlight it and update the converter above.
| # | Fibonacci | T-Shirt Size | Linear (1–7) | Ideal Days | Hours |
|---|---|---|---|---|---|
| 1 | 1 | XS | 1 | 0.5 | 4 |
| 2 | 2 | S | 2 | 1 | 8 |
| 3 | 3 | M | 3 | 2 | 16 |
| 4 | 5 | L | 4 | 3 | 24 |
| 5 | 8 | XL | 5 | 5 | 40 |
| 6 | 13 | XXL | 6 | 8 | 64 |
| 7 | 21 | XXXL | 7 | 13 | 104 |
Understanding Estimation Scales
Every agile team picks an estimation scale that matches their culture and workflow. Here is when each one shines.
The most popular agile estimation scale. Numbers grow non-linearly, reflecting that larger tasks carry more uncertainty.
When to use
When your team has experience with story points and you want to encourage relative sizing over exact time estimates.
Intuitive sizing for non-technical stakeholders. Great for high-level roadmap planning and prioritisation workshops.
When to use
During early discovery, roadmap grooming, or when working with non-technical stakeholders unfamiliar with numbers.
Simple 1–7 scale. Easy to understand but can create false precision — teams often debate 4 vs 5 more than the work deserves.
When to use
When onboarding a new team to agile and you need a simple scale before graduating to Fibonacci.
Represents effort in uninterrupted, focused workdays. Helps bridge story points and calendar time for newcomers to agile.
When to use
When the team wants to bridge the gap between abstract story points and real calendar time during transition periods.
Concrete time estimates. Useful for short-term task tracking but can discourage collaboration and lead to micro-management.
When to use
For individual task tracking within a sprint, bug fixes, or support tickets where exact time accountability matters.
Frequently Asked Questions
Why do agile teams prefer Fibonacci numbers for story points?
Fibonacci numbers grow exponentially, which mirrors how uncertainty grows with task complexity. The wider gaps between larger numbers (e.g., 13 vs 21) prevent teams from wasting time debating small differences they cannot reliably distinguish anyway.
Are story points and hours interchangeable?
Not directly. Story points measure relative complexity and effort, while hours measure clock time. The same feature could take a senior engineer 4 hours and a junior engineer 16 hours — story points capture the inherent complexity regardless of who does the work. Use this converter as a rough reference, not a hard rule.
Which scale should a new agile team start with?
T-shirt sizes (XS–XXXL) are the gentlest introduction — they remove the temptation to treat estimates as exact commitments. Once your team is comfortable with relative sizing, graduating to Fibonacci story points gives you a numerical scale that integrates with velocity tracking and sprint planning tools.
Estimate Together as a Team
Individual estimates miss the wisdom of the crowd. Use Planning Poker to run a real-time estimation session — no signup needed.