PoE budget calculator

What to enter

Use the allocated or conservative maximum power requirement for each phone under its intended configuration. Include expansion modules and powered accessories where their requirements apply. Add other PoE equipment sharing the same available switch budget, such as access points and cameras.

The calculator assumes the phones in this group use the same allocation. For a mixed deployment, run separate groups or calculate their combined load and enter it as other allocated load. Do not use a measured idle reading as a guaranteed maximum.

Count allocated power, then add allowance

Formula and example

Base load = phone count × watts per phone + other allocated load. Required budget = base load × (1 + chosen allowance percentage). Remaining budget = entered switch budget − required budget.

For 24 phones allocated 7 W each and no other load, the base is 168 W. A chosen 20% allowance produces 201.6 W. A switch with 195 W available is short by 6.6 W under those assumptions, even though it has enough physical ports.

Check the limits outside the sum

A total budget does not prove per-port compatibility. Confirm the switch and phone power standards, port allocation behavior, power-supply configuration and any reduced budget in redundant operation. Cable conditions and accessories also matter.

Power consumed by the switch itself belongs in UPS planning, even when it is not part of the advertised PoE output budget.

Validate at deployment

Review the switch's allocation and consumption view with all intended devices connected. Exercise relevant accessories and confirm behavior after a power cycle. Keep the device inventory and budget assumptions with the network plan. The allowance is your planning choice, not a universal standard requirement.