Practical guide
Budget PoE watts with a visible headroom choice
A switch may have enough sockets but still need a larger PoE budget. PortPlan keeps total demand, headroom, and remaining budget visible as separate calculations.
Sum entered per-port demand
The default three access points at 25 W, four cameras at 8 W, and one doorbell at 7 W total 114 W. Quantity multiplies both port occupancy and watt demand.
total PoE demand = sum(per-port watts x quantity)
Apply the reserve percentage
The default 20% headroom turns 114 W into a recommended budget of 136.8 W. Replace the illustrative per-port values with a documented maximum or measured planning value.
recommended budget = total demand x (1 + headroom percent / 100)
Check the two limits separately
Compare the recommended budget with the entered 240 W power budget and inspect the largest 25 W per-port draw. A switch can impose a separate per-port limit even when its aggregate budget has room.
Check your own scenario
Replace the illustrative inputs with measured values and dated specifications.
Open PortPlan PoE BudgetMethod and references
Read the full calculation method and its limits
Method and examples reviewed 2026-09-30. Examples are illustrative; input values and specifications are not independently verified.