Fit check
PoE Power Budget Calculator
Pick the cameras, set IR on or off, enter each cable run. The result gives total load (W), the budget the switch must offer, the ports and PoE standard needed, the switches that fit, and which runs are past the 100m Ethernet limit.
Total load
28 W
4 cameras
Budget needed
34 W
load × 1.2, the switch’s whole-unit PoE budget
Ports needed
4
one per camera
Port standard
802.3af
802.3af (PoE, class 0–3)
Cable runs
- Camera 1: 40m: inside the 100m limit
Switches that fit
- 8 ports · 110W PoE budgetHikvision DS-3E0510P-E 8-Port Gigabit PoE Switch for IP Cameras, 110W Power Budget£76.70
- 16 ports · 130W PoE budgetHikvision DS-3E0318P-E/M 16-Port PoE Unmanaged Network Switch, 130W, SFP Uplink£195.41
- 16 ports · 230W PoE budgetHikvision DS-3E0518P-E 16-Port Gigabit PoE Switch for IP Cameras, 230W Power Budget£196.47
- 16 ports · 240W PoE budgetDahua DH-PFS4218-16ET-240 16-Port Managed PoE Switch, 2 Gigabit Combo Ports, 240W, Hi-PoE£208.66
- 24 ports · 370W PoE budgetHikvision DS-3E0526P-E 24-Port Gigabit PoE Switch for IP Cameras, 370W Power Budget£215.28
How the figures are worked out
Load (W) = sum of camera draw at the camera. Budget needed (W) = load × 1.2: the switch supplies more than the camera receives, because the cable and the switch itself lose power; 20% covers a run up to 100m on Cat5e or Cat6. The whole-unit PoE budget on the switch is the check, not the rating of one port. Ports needed = number of cameras. Per port: 12.95W at the camera for 802.3af, 25.5W for 802.3at, 51W for 802.3bt.
IR on is the figure to plan with: after dark the infrared lights can add 50 to 100% to a camera’s draw, so a total that passes by day can fail at night. The camera draws here are typical spec-sheet values; if your camera’s sheet differs, choose Other and type its watts.
Cable run: Ethernet carries data and PoE for 100m from the switch. A PoE extender is a powered repeater that restarts the 100m: one extender for 100m to 200m, two for 200m to 300m, and so on. The extender itself takes power from the switch, so its draw adds to the load. A run needing more than two extenders is better served by a second switch or fibre.
