Subscriber Capacity Calculator
Estimate maximum subscriber capacity for 2G GSM, 3G UMTS, 4G LTE, and 5G NR networks.
Technology
Physical tower / rooftop / indoor locations
Typically 3 for macro (120° each)
Typical LTE eNB: 1 200–5 000
% of subscribers in RRC-Connected at peak
Subscribers per simultaneous active user (e.g. 8 = 8:1)
Total cells
100 sites × 3 sectors
Max simultaneous RRC connections
Peak concurrent connected users supported
Total subscriber capacity
With 8:1 overbooking at 20% activity
Recommended subscriber limit
80% utilization headroom — leave room for growth
How Subscriber Capacity Is Calculated
Subscriber capacity is derived from the maximum number of simultaneous connections a network can support, divided by the busy-hour active ratio, and multiplied by the overbooking factor.
Max RRC = cells × max_RRC_per_cell
Subscriber capacity = (Max RRC / active_ratio) × overbooking
Recommended limit = subscriber_capacity × 0.80
For simultaneous call capacity, see the VoLTE capacity calculator. For RRC connection utilization, see the RRC capacity calculator.
Frequently Asked Questions
What is subscriber capacity in a mobile network?▾
Subscriber capacity is the maximum number of end-users a network can serve while maintaining acceptable service quality. It is derived from the simultaneous capacity of the radio access network — how many users can be active at the same time — divided by the busy-hour active ratio (the fraction of subscribers using the network simultaneously at peak), then multiplied by an overbooking factor that accounts for the statistical unlikelihood that all subscribers are active at once.
What is the overbooking ratio?▾
The overbooking ratio represents how many subscribers share each simultaneous active connection slot. Because not all subscribers are active at the same time, operators provision fewer radio resources than total subscribers. A ratio of 8:1 means 8 subscribers are provisioned for each peak simultaneous connection. Residential networks typically use 8–15:1; enterprise networks use 3–5:1. Higher overbooking lowers cost but increases congestion risk during unexpected traffic spikes.
What is busy-hour active ratio?▾
The busy-hour active ratio is the percentage of total subscribers simultaneously in RRC-Connected state (4G/5G) or holding an active call/data session (2G/3G) during the network's peak hour. Typical values are 10–20% for residential LTE, 20–30% for 5G, and 2–5% for 2G voice-focused networks. A higher active ratio means each subscriber consumes more capacity, reducing total subscriber ceiling for a given radio network.
How does 2G subscriber capacity differ from 4G/5G?▾
2G GSM uses the Erlang B traffic model on a fixed number of TCH (Traffic Channel) timeslots per cell. Subscriber capacity is derived from the total Erlang capacity of the network divided by the traffic each subscriber generates (BHCA × call duration). 3G UMTS uses a noise-rise pole capacity model based on Eb/No and voice activity. 4G LTE and 5G NR use RRC connection limits — the number of simultaneous connected users the base station can maintain. Each model reflects the fundamentally different radio access technology.