Sprint forecast calculator
For Scrum and other agile teams: turn the story points left in your backlog and your team's recent velocity into a release date. Not one date, but a range with probabilities, so you can promise a date you will actually hit. Free, no sign-up.
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Free sprint forecast by ISTRALLEN. Your numbers stay in your browser unless you share a link. Need estimates first? Try Planning Poker.
Why one date is the wrong answer
The usual way agile teams forecast is to divide the backlog by average velocity: 120 points at 20 per sprint is 6 sprints. The catch is that velocity varies from sprint to sprint, and a date built on the average sits in the middle of the possible outcomes. As Doc Norton puts it in an InfoQ interview on velocity, velocity forecasts are usually around 50% probable: a coin toss. How close to 50% depends on your numbers, so the calculator shows the exact chance for your backlog.
This calculator shows the average-based date, but leads with the date you will hit 85% of the time. That is the one to give to a client or a stakeholder.
How the forecast works
- Three simple scenarios. What happens if every sprint goes like your best one, your average one, and your worst one.
- A Monte Carlo simulation. With 3 or more sprints of history, the calculator plays out your remaining work 10,000 times, picking each future sprint's velocity at random from your real sprints. The dates you see are the points where 50%, 85% and 95% of those runs finished. It assumes future sprints look like your past ones, so with only a few sprints treat the percentages as a rough guide.
- Scope growth. Backlogs rarely stand still. If new work keeps arriving, set it as a percentage of the initial backlog per sprint, and every scenario takes it into account.
- Your deadline. Add one, and the calculator tells you the chance of making it.
FAQ
How do I calculate sprint velocity?
Add up the story points the team actually completed in each of the last 3 to 5 sprints and take the average. Count only finished work, not what was planned. The average alone hides how much velocity varies, so this calculator also uses each past sprint on its own to show the range.
How do I convert story points to weeks or hours?
Story points are not hours, so there is no fixed rate. The bridge is your team's velocity: if the team finishes about 20 points in a two-week sprint, 120 points is about 6 sprints, or 12 weeks. The calculator does this for you and shows how much the date can move.
How do I turn story points into a delivery date?
Enter the story points left in the backlog and how many points your team completed in recent sprints. The calculator converts that into sprints and then into calendar dates, using your sprint length and start date.
Why not just divide the backlog by average velocity?
Because velocity varies, and a date based on the average sits in the middle of the possible outcomes, so it is often close to a 50/50 bet. The calculator shows the exact chance for your numbers and leads with the date reached in 85% of simulated runs.
What is the Monte Carlo forecast?
With 3 or more sprints of history, the calculator plays out the remaining work 10,000 times, picking each future sprint's velocity at random from your past sprints. The 50%, 85% and 95% dates are where that share of runs finished. It assumes future sprints look like your past ones, so with 3 to 5 sprints the percentages are a rough guide.
How many sprints of history do I need?
Three or more unlock the probabilities. With fewer, use the average option: the calculator then assumes velocity varies by about 20% either way and shows a best, average and worst case.
What does scope growth mean?
Most backlogs keep growing while the team works: new requests, bugs, follow-ups. Set the growth as a percentage of the initial backlog per sprint. If scope grows as fast as the team delivers, the forecast tells you it will never finish at this pace.
Can I use estimates from Planning Poker?
Yes. In our free Planning Poker, the session history has a link that opens this forecast with the total story points already filled in. It appears for numeric decks; T-shirt sizes don't add up to a number.
Is my data stored anywhere?
No. The forecast runs in your browser and your numbers are kept in its local storage. The only exception is a share link you create: the numbers are written into that link.
Forecast says you won't make it?
This tool is made by ISTRALLEN. We build backends, payment and API integrations, and production AI features, and can take a module or an integration off your team's plate.