Backlog Completion Time Calculator
A backlog clears at the rate your team completes work minus the rate new work arrives. This calculator takes your backlog size, your velocity per sprint, the new items added each sprint, and the sprint length, then projects how many sprints and weeks it will take to finish. If incoming work matches or exceeds velocity, it flags that the backlog will not clear at current rates, so you can adjust capacity or scope before committing to a date.
Backlog completion formula
net throughput = velocity - new work per sprint
sprints to clear = ceil( backlog / net throughput )
weeks to clear = sprints to clear * sprint length
if net throughput <= 0: backlog never clears
Net throughput is the rate the backlog actually shrinks each sprint. Sprints to clear is rounded up because you cannot finish a partial sprint. Weeks to clear converts sprints to calendar time using your sprint length.
Worked example
For a backlog of 120, velocity of 20, 5 new items per sprint, and 2-week sprints: net throughput = 20 - 5 = 15 per sprint. Sprints to clear = ceil(120 / 15) = 8. Weeks to clear = 8 * 2 = 16. Because net throughput is positive, the outlook is "Clearing".
Backlog completion: frequently asked questions
How do I estimate when a backlog will be done?
Divide the remaining backlog by your net throughput per sprint, which is your velocity minus the new work added each sprint. That gives the number of sprints. Multiply by the sprint length to get weeks. If new work arrives as fast as you complete it, net throughput is zero and the backlog never clears.
What is velocity?
Velocity is the amount of work, in story points or items, that a team completes in one sprint. It is measured from past sprints, not guessed. Using an average of several recent sprints gives a more stable estimate than a single sprint, which can be unusually high or low.
Why account for incoming work?
Backlogs rarely stand still. New requests, bugs, and scope arrive while the team works. If you ignore incoming work, your completion estimate will be too optimistic. Subtracting the new items added per sprint from velocity gives the net rate at which the backlog actually shrinks.
What if velocity is lower than incoming work?
If new work per sprint is greater than or equal to velocity, the net throughput is zero or negative and the backlog grows rather than shrinks. The calculator flags this as the backlog never clearing at the current rates, signalling that you need more capacity, less incoming scope, or both.
Sources and method
- The projection is direct arithmetic on the backlog, velocity, incoming work, and sprint length you enter, computed exactly by this tool.
- Velocity should be measured from your own past sprints; it is an editable input here, not a fixed assumption.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.