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PoE Budget Calculator

Checks whether the active PoE endpoints on a switch fit within the switch's total PoE budget, accounting for IEEE 802.3af/at/bt class reservations and estimated cable loss.

Switch PoE budget (W — from switch spec)

Port PoE class

Active powered ports

Avg cable run (meters, optional)

Budget headroom % (default 0)

Limitations: Worst-case class reservation — most endpoints draw less in practice. Cable loss model is an approximation; real loss depends on Cat rating, wire-gauge, and bundle derating (TIA-568). Does NOT model LLDP power-negotiation dynamics.

What to do next: For mission-critical deployments, set headroom ≥ 15%. If you're near the edge, split the load across two switches or use per-port LLDP-negotiated power where the endpoints support it.