Burndown Chart Calculator

What this calculator estimates

A burndown chart compares the amount of work that should remain in a sprint with the amount that actually remains. This calculator turns your sprint duration, committed scope, and daily completed work into an ideal line, an actual line, and a required-finish line. It also reports the current average burn rate, the pace needed from today onward, the variance from plan, and a simple completion forecast.

The tool is designed for sprint-level monitoring rather than individual performance assessment. A chart that moves unevenly is normal because stories are often completed in batches. Use the result to surface blockers, scope changes, review bottlenecks, and forecasting risk during team discussions.

Input guide

• Sprint duration is the number of working days available. Enter a whole number from 1 to 60. A longer sprint reduces the ideal daily pace for the same scope, while a shorter sprint raises it. Do not include weekends or holidays unless your team treats them as active sprint days.
• Total story points is the committed scope at the start of the sprint. It is required and must be zero or greater. Story points work best when the team applies a stable estimation scale. You can also use tasks or hours, but every daily entry must use the same unit.
• Story points burned each day records completed work, not work merely started. Leave future days blank. Enter 0 when a day has elapsed but nothing was completed; this ensures the calculator counts the day in the current velocity. Negative values are rejected because they usually represent scope added, which should be tracked separately rather than treated as completed work.

When scope changes materially during a sprint, decide whether to preserve the original commitment line or rebaseline the total. Preserving the original line makes scope growth visible; rebaselining makes the chart easier to use as a forward-looking execution plan. Whichever method you choose, apply it consistently.

How the calculations work

The ideal line assumes an even burn from the starting scope to zero at the end of the sprint. For day d, total work W, and duration D:

The current burn rate equals cumulative completed work divided by elapsed days. The required burn rate equals remaining work divided by remaining days. The completion forecast extends the current average pace: elapsed days plus remaining work divided by the current burn rate. If the current rate is zero while work remains, the forecast is reported as unavailable rather than producing an infinite value.

The methodology is compatible with the general burndown practice described in the Scrum Guide. Additional practical background is available from Atlassian’s burndown chart guide and the Agile Alliance glossary.

Result-by-result interpretation

• Story points remaining is committed scope minus cumulative completed work, capped at zero. A zero result means the entered scope is fully burned.
• Current burn rate is the team’s average completed work per elapsed day. A higher rate shortens the forecast, but a one-day spike may not be sustainable.
• Required burn rate is the pace needed to reach zero by the planned final day. If it exceeds the current rate, the sprint is trending behind unless performance improves or scope is reduced.
• Variance from ideal compares actual remaining work with ideal remaining work on the current day. A positive variance means more work remains than planned; a negative variance means less work remains.
• Forecast completion projects the finish day using the current average pace. It is a directional indicator, not a promise, because future throughput and scope may change.

Reading the chart and schedule

The blue ideal line descends evenly from total scope to zero. The teal actual line uses only elapsed days and reflects your entered daily burn. The purple required line starts from today’s actual remaining work and shows the straight-line pace needed to finish on time. When the actual line sits above the ideal line, the team has more work remaining than the even-burn plan. When it sits below, the team is ahead of that plan.

The daily schedule exposes the same model in table form. “Ideal remaining” is the planned benchmark. “Burned today” is the direct input. “Cumulative burned” is the running total. “Actual remaining” is available only through the latest entered day. “Variance” is actual remaining minus ideal remaining, so positive values indicate lag against the ideal benchmark.

Common mistakes and better review habits

Avoid filling future days with zeros, because that makes the calculator treat them as elapsed and depresses the current velocity. Do not mix story points with hours or task counts. Do not interpret a flat line as automatically poor performance: work may be in review, testing, or integration and then close in a batch. Finally, separate scope added from work completed so the chart does not hide the cause of a rising or flat remaining-work line.

Use the chart as a conversation prompt. Investigate sustained variance, compare the required pace with realistic team capacity, and record decisions about blockers or scope. The exported workbook preserves current inputs, results, chart series, and the full daily schedule for review or reporting.