Story Points Delivered Is Used To Calculate Velocity

Understanding how story points delivered is used to calculate velocity for Scrum teams.

Summary Table: Velocity Metrics

Metric	Value	Description

What is “Story Points Delivered Is Used to Calculate Velocity”?

In the world of Agile software development, the concept that story points delivered is used to calculate velocity is a fundamental principle of team performance tracking. Velocity is a metric that measures the amount of work a team can tackle during a single sprint and is the primary tool used for long-term planning and capacity forecasting.

Many project managers use this data to determine how quickly a team can work through a product backlog. Because story points delivered is used to calculate velocity, it provides a historical average that removes guesswork from the estimation process. Scrum masters use this metric not to compare teams, but to help a single team understand their own rhythm and output capacity over time.

Common misconceptions include using velocity as a productivity metric or a performance KPI for individuals. In reality, the fact that story points delivered is used to calculate velocity means it is a measure of volume and predictability, not necessarily quality or value. A team’s velocity is specific to their unique estimation scale and environment.

Velocity Formula and Mathematical Explanation

The calculation is straightforward but requires consistent data. The core idea is that the sum of story points delivered is used to calculate velocity by dividing that sum by the number of sprints analyzed.

The Formula:

Average Velocity = (S1 + S2 + S3 + ... + Sn) / n

Where:

• S: The number of story points completed (delivered) in a specific sprint.
• n: The total number of sprints in the observation window (typically the last 3 to 5 sprints).

Variable	Meaning	Unit	Typical Range
Points Delivered	Total points meeting ‘Definition of Done’	Story Points	15 – 60 per sprint
Sprint Count	Number of iterations averaged	Sprints	3 – 5 Sprints
Backlog Size	Remaining work in the queue	Story Points	100 – 1000+ Points
Predictability	Actual vs. Planned points ratio	Percentage (%)	80% – 100%

Practical Examples (Real-World Use Cases)

Example 1: The Stable Development Team

A team finishes three sprints. In Sprint 1, they deliver 20 points. In Sprint 2, they deliver 22 points. In Sprint 3, they deliver 18 points. To find out how story points delivered is used to calculate velocity here, we add them (20+22+18 = 60) and divide by 3. Their average velocity is 20 points. If they have a 100-point backlog, they will likely need 5 more sprints to finish.

Example 2: The High-Growth Startup Team

A new team starts with a velocity of 10. By the second sprint, they deliver 25 points, and by the third, 40 points. While story points delivered is used to calculate velocity for them at an average of 25, the trend suggests they are still “forming” and their velocity has not yet stabilized. Planning based on the average might be risky until the numbers plateau.

How to Use This Velocity Calculator

1. Enter Delivered Points: Input the total story points your team successfully delivered in the last three sprints. Remember: only “Done” work counts.
2. Set Planned Points: For the most recent sprint, enter what the team originally committed to. This helps calculate your team’s predictability.
3. Input Backlog Size: If you know your total remaining product backlog in story points, enter it to see an estimated completion timeline.
4. Review Results: The calculator immediately updates your average velocity, predictability, and total points delivered.
5. Analyze the Trend: Look at the SVG chart to see if your velocity is increasing, decreasing, or stable over time.

Key Factors That Affect Velocity Results

• Team Composition: Adding or removing members immediately changes how story points delivered is used to calculate velocity. New members often lower velocity temporarily due to onboarding overhead.
• Sprint Duration: Velocity is relative to sprint length. A two-week sprint will naturally have different numbers than a four-week sprint.
• Definition of Done (DoD): If the DoD becomes stricter (e.g., adding automated testing requirements), the story points delivered is used to calculate velocity will likely drop as tasks take longer to complete.
• Technical Debt: High technical debt slows down development, leading to fewer story points delivered over time.
• Estimation Accuracy: If a team’s understanding of a “point” changes, the velocity metric will shift even if the actual output remains the same.
• Team Focus: Excessive meetings, context switching, or production support work reduces the time available for backlog items, lowering the velocity.

Frequently Asked Questions (FAQ)

1. Why is story points delivered used to calculate velocity instead of hours?

Story points account for complexity, risk, and uncertainty, whereas hours only measure time. Using points allows for more stable long-term forecasting as team members become more efficient.

2. Should we include partially completed stories in velocity?

No. In strict Agile, only stories that meet the full “Definition of Done” are counted. Partial points are not used when story points delivered is used to calculate velocity to ensure high quality and clear progress.

3. What is a “good” velocity?

There is no “good” or “bad” number. Velocity is a relative internal metric. A velocity of 20 is not better than a velocity of 10 if the second team uses a different scale.

4. How often should we recalculate velocity?

Velocity is recalculated at the end of every sprint. Usually, a rolling average of the last 3-4 sprints is used for planning the next iteration.

5. Can we compare velocity between two different teams?

No. Since every team estimates differently, comparing their velocities is misleading. The fact that story points delivered is used to calculate velocity means the number is only valid for the team that generated it.

6. Does velocity include bugs or maintenance?

Generally, velocity tracks work that adds new value (stories). However, some teams choose to point bugs to see how maintenance affects their capacity. Consistency is key.

7. Why is my team’s velocity decreasing?

Common reasons include increased technical debt, team members being on leave, a change in work complexity, or an unclear product backlog.

8. How does predictability relate to velocity?

While story points delivered is used to calculate velocity to show capacity, predictability shows how well the team understands their own capacity. A team with a velocity of 30 that always plans 30 is more predictable than a team that plans 50 but delivers 30.

Related Tools and Internal Resources

• Agile Estimation Guide – Learn how to assign points to stories before the sprint.
• Scrum Sprint Planning Tool – Use your velocity results to plan your next sprint effectively.
• Burn Down Chart Basics – Track daily progress within a sprint once your velocity is set.
• Team Capacity Planner – Adjust velocity based on team holidays and available hours.
• Relative Sizing Tips – How to ensure your story points stay consistent over time.
• Agile Metrics Dashboard – Combine velocity with lead time and cycle time for a full view.