Branch Lifetime Calculator
Calculate average branch lifetime from creation to merge/deletion and flag long-lived branch risk.
Inputs
Sum of days-open across all branches measured (creation to merge or deletion).
Number of branches included in the measurement.
Days open beyond which a branch is considered long-lived and higher risk.
Number of branches that stayed open longer than the threshold.
Average Branch Lifetime
6.0days
Long-Lived Branch Risk
Moderate
Share of Long-Lived Branches
22.5%
Step by step
Avg lifetime: sum durations / branches
240 / 40
= 6.0 days
Long-lived share (over threshold)
9 / 40
= 22.5%
How it works
Branch lifetime tracks how long feature branches stay open before merging or being deleted. Formula: avg_lifetime = sum(branch_durations) / branches. Long-lived branches accumulate more divergence from the base, raising merge conflict risk and making code review harder — trunk-based development practices explicitly target very short branch lifetimes (hours to a couple of days).
Formula
avg_lifetime_days = sum_of_branch_durations / branch_count
- sum_of_branch_durations
- Sum of days-open across all branches
- branch_count
- Number of branches measured
Frequently Asked Questions
How long should a feature branch typically live?
Trunk-based development teams often target under 1-2 days; many mainstream teams target under a week. Beyond 2 weeks, divergence and conflict risk climb sharply for most codebases.
How do I measure branch lifetime in Git?
Compare the branch's first commit timestamp (or creation event from your Git host's API) to its merge or deletion timestamp. GitHub/GitLab APIs expose PR creation and merge times directly, which is usually a cleaner proxy.
Why do long-lived branches increase risk?
The longer a branch lives, the more the base branch moves on without it — increasing both the volume of changes to review at once and the odds that the same files were touched on both sides, causing conflicts.
What practices shorten branch lifetime?
Smaller PRs scoped to a single change, feature flags to merge incomplete work safely, and fast CI/review turnaround all reduce how long a branch needs to stay open before merging.
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