Calculate the maximum number of builds that can run concurrently given resources.
The maximum number of builds Jenkins can run at any single instant is bounded strictly by the total executor count across all connected, online agents — one executor runs exactly one build at a time. When the number of simultaneously requested builds exceeds available executors, the excess forms a queue rather than running immediately, waiting for an executor to free up; this is the same constraint that drives wait time in the build queue calculator.
queuedBuilds = max(0, requestedBuilds - executors)
Not by default for a single job's main flow, but a declarative pipeline with a `parallel {}` block launching multiple `agent` directives effectively consumes one executor per concurrent branch, so a single pipeline run can occupy several executors at once.
Yes in practice — this calculator assumes all executors are fungible and available to every requested build; if builds require specific labels (e.g. `docker`, `gpu`), the effective competing pool is only the executors matching that label, not the cluster-wide total.
They remain queued indefinitely (subject to any configured queue timeout) until an executor becomes free or the job is manually cancelled; persistent queuing under peak load is a strong signal to add executors or improve throttling.