Story Point Estimator
Estimate story points using Fibonacci, T-shirt sizes, or custom scales with estimation history and statistics. All processing runs in your browser.
About This Tool
The Story Point Estimator is a free, browser-based tool that helps agile teams estimate the relative effort of user stories and tasks. Story point estimation is a cornerstone of Scrum and agile planning because it separates effort from time, enabling more honest and consistent discussions about complexity and risk.
Choose from three built-in estimation scales: Fibonacci (0, 1, 2, 3, 5, 8, 13, 21), T-shirt sizes (XS through XXL), or a fully custom scale you define yourself. Click an estimation card to assign a value to the current story, then review your estimation history and aggregate statistics including average, median, mode, and total points.
The distribution chart shows how your estimates are spread across the scale, helping you spot estimation biases -- for example, if your team gravitates toward a single value. You can export the full estimation history as a CSV file for importing into Jira, Azure DevOps, or any spreadsheet application.
All processing runs entirely in your browser. No data is sent to any server, and no account or signup is required. Estimation history is saved to your browser's localStorage so you can return and continue estimating without losing data.
This tool pairs well with the Sprint Velocity Calculator for tracking how many estimated points your team actually delivers, the Meeting Cost Calculator for understanding the cost of estimation sessions, and the Pomodoro Timer for time-boxing your estimation meetings.
How to Use
- Choose an estimation scale at the top: Fibonacci, T-Shirt Sizes, or Custom. For custom scales, type a value and click + to add it.
- Enter a story title (e.g., "User login API" or "PROJ-42"). If left blank, the tool auto-generates a numbered title.
- Optionally enter a description with acceptance criteria or notes to provide context for the estimation.
- Click one of the estimation cards to select your estimate. The selected card is highlighted.
- Click Add Estimation or press Ctrl+Enter to record the estimation in your history.
- Review the Estimation History list and the Estimate Distribution chart to see patterns in your estimates.
- Check the Statistics panel for total estimations, total points, average, median, and most common estimate.
- Click CSV to export your full estimation history, or press Ctrl+Shift+C to copy a formatted report to your clipboard.
Popular Story Point Estimation Guides
FAQ
Is my data safe when using this tool?
Yes. All processing runs entirely in your browser using JavaScript. No data is sent to any server. Estimation data is stored only in your browser's localStorage and never transmitted anywhere. You can clear it at any time.
What are story points?
Story points are a relative unit of measure used in agile development to estimate the effort, complexity, and risk involved in implementing a user story. Unlike hours, story points compare work items to each other rather than predicting absolute time.
Why use Fibonacci numbers for estimation?
The Fibonacci sequence (1, 2, 3, 5, 8, 13, 21) naturally increases the gap between consecutive values. This reflects the reality that the larger a task is, the less precisely we can estimate it. The growing gaps discourage false precision on large items.
When should I use T-shirt sizes instead of Fibonacci?
T-shirt sizes (XS through XXL) are useful for high-level estimation when precision is not needed -- such as during roadmap planning, initial backlog grooming, or when working with non-technical stakeholders who find numbers confusing.
Can I create my own custom scale?
Yes. Select the Custom scale option and type any values you want to add. Common alternatives include powers of 2 (1, 2, 4, 8, 16), linear scales (1-10), or any scheme your team prefers.
How do T-shirt sizes map to numeric values?
The tool maps T-shirt sizes to Fibonacci-like numbers for statistics: XS=1, S=2, M=3, L=5, XL=8, XXL=13. This enables meaningful averages and totals while keeping the T-shirt abstraction for estimation.
Can I use keyboard shortcuts?
Yes. Press Ctrl+Enter to add the current estimation to the history. Press Ctrl+Shift+C to copy the full estimation report to your clipboard.
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