Backlog forecast calculator
A backlog forecast is items remaining divided by velocity, widened by how much that velocity varies. The output is a range of dates, because a single date derived from an average is wrong roughly half the time by construction.
Backlog forecast, step by step
Dividing by average velocity gives you the fifty-fifty date: the day you have an even chance of making. Presenting that as the date is where delivery forecasting usually goes wrong, and it is a mathematical certainty rather than bad luck.
Using the spread of your last several sprints gives a range instead — an optimistic date from your best rate and a safe one from your worst. Quote the pessimistic end to stakeholders. A team that commits to its 85th-percentile date and hits it builds more trust than one that commits to its average and misses half the time.
Where this number misleads you
The forecast assumes the backlog stops growing, which it does not. Scope added after the forecast moves the date and nobody updates the slide. Track the backlog’s growth rate alongside the burn rate — if items arrive faster than they are finished, there is no completion date at all and the honest answer is to say so.
Questions people ask
How do I forecast when a backlog will be done?
Divide remaining items by your velocity per sprint, then produce a range using your fastest and slowest recent sprints rather than just the average. Report the pessimistic end as the commitment date, and state the assumption that no new scope arrives.
Why should a forecast be a range rather than a date?
A date from average velocity is the fifty-fifty date — you will miss it about half the time no matter how well the team performs. A range shows the uncertainty that genuinely exists, and quoting the safe end means commitments you actually meet.
How many sprints of history do I need?
At least three, preferably five or more, from the same team with roughly the same composition. Fewer than three gives you no measure of variability, which is the part of the forecast that matters most. A reorganisation resets the history.
When one number is not the job
This page works out one number. PikoPM’s Capacity planner plans a real team — holidays, part-timers, three countries — instead of one number at a time.
Open Capacity planner — it needs an account, and the Free plan covers it.