Free tool

PoE Switch Power Budget Calculator UK 2026

Work out your total PoE wattage, port count, and the right switch size before you buy. Built for UK CCTV, Home Assistant, and home network installs.

1. Start with a quick preset

Pick a common setup to pre-fill the calculator, or build your own mix below.

2. Add your PoE devices

Enter each device type, how many you have, and the typical watts per device. The calculator updates live.

Based on standard 802.3af / 802.3at / 802.3bt PoE rules. Use your device spec sheets for exact draw.

Need a buying shortlist? Compare the best PoE switches.

How to calculate PoE switch power budget

The simple formula is: sum all device wattage, then add a bit of headroom. If your cameras average 8W each and you have four of them, that is 32W before you add access points, doorbells, or other PoE gear. Add 20% headroom and you are already at 38.4W — so a 55W switch is technically fine, but a 65W switch gives you breathing room.

The other limit is port count. A switch can have enough watts but still run out of ports. That is why this calculator gives you both the minimum PoE budget and the number of ports you should target, including spares.

What wattage do common PoE devices use?

  • Standard CCTV camera: about 6–10W
  • Floodlight / spotlight camera: about 10–15W
  • PTZ camera: often 15–25W, sometimes more
  • WiFi access point: usually 8–15W
  • Video doorbell / intercom: around 5–10W

If any single device needs more than 15.4W, you need PoE+ (802.3at). If a device can exceed 30W, you need PoE++ (802.3bt) or a separate power supply.

Recommended UK PoE gear

These are the two switches that make sense for most home builds we see on filce.uk. For CCTV-heavy installs, the full PoE switch guide breaks down the trade-offs in more detail.

GiGaPlus GP-S25-0402P 4x 2.5G PoE+ ports, 65W budget — best for compact AP and desk-rack builds. YuanLey 18-Port PoE Switch 16 PoE ports, 250W budget — the easy pick for bigger CCTV systems. Reolink RLN36 NVR Ideal if this is a camera build and you want a dedicated recorder alongside the switch.

FAQ

Do I need a managed PoE switch?

Not always. For a straightforward CCTV setup, an unmanaged switch is fine. If you want to isolate cameras on their own VLAN, or keep your IoT devices off your main LAN, a managed switch is worth the extra money.

Can I mix cameras and WiFi access points on the same switch?

Yes — as long as the switch has enough budget for the combined load and enough ports for growth. This is exactly what the calculator is for.

What if my total goes over 250W?

That is the point where you should split the load across two switches or move to a more serious managed rack switch. For CCTV specifically, it may also be time to separate storage and power with an NVR plus dedicated PoE switching.