Estimate the number of IoT sensors and gateways required for a deployment. Site count, sensing points per site, redundancy, spare inventory, and gateway device capacity are combined into an install and procurement plan.
Procured sensors include installed units and uninstalled spares. Gateways are sized from installed sensors, then increased by a reserve allowance.
Radio range, building layout, channel limits, message rate, backhaul, power, and vendor-specific concurrency limits may require more gateways than device count alone.
For 120 sites with 6 points and one sensor per point, 720 sensors are installed. An 8% spare allowance gives 778 sensors to procure. At 100 sensors per gateway, eight active plus one reserve means nine gateways.
Redundant sensors are installed and operate in parallel; spares remain uninstalled until needed.
Uninstalled spare sensors do not communicate, so they do not consume gateway capacity.
Count physical sensor devices, not data fields, when one device provides multiple measurements.
Use a reliable tested capacity that accounts for message rate, protocol overhead, and local radio conditions.
Procurement and installation require whole devices, so fractional requirements are rounded upward.
| Input | Role in the estimate |
|---|---|
| Deployment sites | Locations receiving the same sensor design. |
| Sensing points per site | Distinct measurements or monitored assets. |
| Sensors per point | Parallel sensors installed at each point. |
| Spare sensor allowance | Uninstalled stock for failures and replacements. |
| Sensors per gateway | Reliable supported device count per gateway. |