PoE Switch Power Budget Calculator
Size the switch by the three limits that matter at the same time: powered ports, total PoE watts and aggregate camera traffic.
How the calculator works
The base device load is the number of cameras multiplied by each camera's maximum rated PoE draw. The planning target adds your selected headroom. The switch is considered adequate only if it has enough powered ports and its total PoE budget exceeds the planning target.
Bandwidth is calculated separately from power. The calculator adds the configured camera bitrates and compares that traffic with the selected shared uplink. A switch can have plenty of watts and still have a network bottleneck, or vice versa.
Why maximum watts matter
Infrared LEDs, white lights, heaters, speakers and PTZ motors can push a camera above its normal daytime consumption. Use the manufacturer datasheet's maximum draw when possible rather than a measured idle number.
PoE standards are per-port limits
| Family | Common source-side ceiling | Typical camera fit |
|---|---|---|
| 802.3af / PoE | 15.4 W | Many fixed cameras |
| 802.3at / PoE+ | 30 W | Higher-output IR, mini PTZ |
| 802.3bt / PoE++ | 60 W or higher by type | Large PTZ, heaters, multi-sensor cameras |
The final camera datasheet controls the required standard. The calculator uses the highest entered camera wattage only as a planning clue.
Related planning guides
8-camera PoE switch sizing · 16-camera PoE switch sizing · PoE cable distance · bandwidth calculator