How this calculator works
A burndown chart plots the work left against time. The ideal line falls evenly from the committed points to zero at the end of the sprint. This calculator reads the remaining-points series you enter, compares the latest value with the ideal line for that day and estimates the finish day from the average rate so far. The list starts with the first day's end-of-day value, so its length is the number of elapsed days. Recalculate after each daily stand-up to see the trend.
Formula
Ideal points per day = committed points / sprint days. Ideal remaining at day n = max(0, committed × (1 - n / sprint days)). Average points per day = (committed - remaining) / elapsed days. Projected finish day = elapsed days × committed / (committed - remaining). Variance = remaining - ideal remaining.
Worked example
With 100 points over 10 days the ideal line loses 10 points a day. The entered series ends day four at 65 points, so 35 points are done at 8.75 a day and the ideal remaining is 60. The team is five points behind, and the current rate projects a finish on day 11.4.
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Frequently asked questions
Why is the projected finish after the sprint?
The projection simply extends the average rate. In the example the team completed 35 points in four days, slower than the ten a day the plan needs, so the same rate finishes after the sprint ends. Scope changes and blocked work can make the projection move sharply, so update it daily.
Why is there no chart?
This engine returns numeric readouts and text, so it reports the figures a burndown chart would show rather than drawing the chart. Plot the remaining-points list in a spreadsheet for the visual line.
Should weekends count as days?
No. Use working days only, and keep the sprint length in working days too. If your team finishes some points mid-day, enter the end-of-day value after each working day.