Cell Availability is an Availability-category KPI that measures the proportion of a given reporting period during which a cell was operationally able to carry traffic - that is, unlocked, in service, and not blocked by a fault. It is calculated as the ratio of the time the cell was actually available to the total duration of the reporting period, expressed as a percentage. Periods of planned maintenance (administrative locking) are sometimes excluded or tracked separately from unplanned outages, depending on operator reporting policy, since the two have different operational implications. This KPI is critical for service level agreement (SLA) reporting and for identifying cells with recurring stability issues such as repeated automatic resets, hardware faults, or transport outages. It is distinct from throughput-based, handover-based, or alarm-count-based ratios, which belong to other KPI categories and answer different operational questions.