Sprint velocity calculator
Type the story points (or any unit) your team finished in recent sprints, the size of the remaining backlog and the sprint length. You get the average velocity, the average of the last three sprints, the spread, and a forecast of how many sprints and weeks the backlog needs at the average, best and worst pace.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter the points completed in each past sprint, oldest first.
- Enter the remaining backlog in the same unit.
- Enter the sprint length in weeks.
- Read the number of sprints and weeks, and compare the best and worst cases.
How it works
- Average velocity = sum of velocities ÷ number of sprints
- Recent average = average of the last three values (or of all, if fewer)
- Standard deviation: the sample standard deviation, √(Σ(v − average)² ÷ (n − 1))
- Sprints needed = backlog ÷ velocity, rounded up; best uses the highest velocity, worst the lowest
- Weeks = sprints needed × sprint length
Example
Five sprints finished 21, 25, 19, 23 and 27 points, 180 points remain and sprints last two weeks.
- Average = 115 ÷ 5 = 23; last three = (19 + 23 + 27) ÷ 3 = 23
- Sprints needed = 180 ÷ 23 = 7.83 → 8 sprints, which is 16 weeks
- Best case 180 ÷ 27 = 6.67 → 7 sprints; worst case 180 ÷ 19 = 9.47 → 10 sprints
- Standard deviation: deviations −2, 2, −4, 0, 4, squares add up to 40, √(40 ÷ 4) = 3.16
Tips
- Use the same estimation scale over time; re-estimating the backlog in different points breaks the forecast.
- Plan holidays and team changes as lower velocity for those sprints.
- Share the range (7–10 sprints), not just the single number; it sets honest expectations.
Frequently asked questions
What is sprint velocity?
The amount of work a team finishes in one sprint, usually in story points of items that met the definition of done. Partly done items do not count. Velocity is a planning aid for that one team, not a score to compare teams.
How is the number of sprints calculated?
Remaining backlog ÷ average velocity, rounded up, because a sprint is either run or not. With 180 points and an average of 23 that is 7.83, so 8 sprints. Multiplying by the sprint length gives the weeks.
What are the best and worst cases?
The same division with your highest and your lowest velocity so far. They give a simple range: if the team keeps its best pace, and if every sprint is as slow as its slowest one.
How many sprints should I enter?
Three to six recent sprints are typical. Very old sprints may reflect a different team or way of working; the average of the last three shows the current trend next to the full average.
Does the backlog stay the same?
This forecast assumes it does. Backlogs usually grow as work is discovered; if yours grows by a known amount per sprint, subtract that from the velocity before entering it.