This calculator measures how intensively a public EV charger is used over a selected reporting period. It compares occupied charging time with total available connector time and also reports sessions per day and average energy delivered per occupied hour.
Site operators, property managers, and charging-network analysts can use these metrics to evaluate congestion, expansion needs, maintenance windows, or underused assets. Utilization alone does not show profitability or customer satisfaction, so it should be read alongside energy sales, downtime, queue data, and operating costs.
1. Enter connector count
Count independently usable charging connectors.
2. Set the reporting period
Enter the number of days represented by the operating data.
3. Enter daily operating hours
Use 24 for always-open sites or the actual daily window.
4. Add occupied hours
Sum the time connectors were in use during the period.
5. Add sessions and energy
These optional operating totals support activity metrics.
6. Review utilization
Compare occupied time with available connector-hours.
Available connector-hours = Connectors × Days × Operating hours per day
Utilization (%) = Occupied connector-hours ÷ Available connector-hours × 100
Sessions per day = Sessions ÷ Days
Energy per occupied hour = Energy delivered ÷ Occupied hours
The main result is the share of available connector time that was occupied.
If occupied hours include blocked, idle, or faulted time, the result is occupancy utilization rather than active-energy utilization.
Given: 4 connectors, 30 days, 24 operating hours per day, 900 occupied hours, 620 sessions, and 18,000 kWh delivered.
Calculation: Available connector-hours = 4 × 30 × 24 = 2,880. Utilization = 900 ÷ 2,880 × 100 = 31.25%. Sessions per day = 620 ÷ 30 = 20.67. Energy per occupied hour = 18,000 ÷ 900 = 20 kWh.
Result: Charger utilization is 31.25%.
The site used just under one-third of its available connector time during the period.
Include it if your goal is connector occupancy. Exclude it when measuring active charging utilization only, but keep the definition consistent across periods.
It should not when connector count, operating hours, and occupied hours use the same basis. A value above 100% usually signals overlapping or incorrectly aggregated records.
There is no universal threshold. Queue patterns, peak-hour utilization, service targets, and expansion cost matter more than an all-day average alone.
You may reduce operating hours to reflect planned unavailability, or keep full availability and report downtime separately. State the method whenever periods are compared.
Two sites can have the same time utilization but very different session turnover. Sessions per day helps distinguish many short visits from fewer long ones.