PoE power budget calculator
Total planned powered-device allocations and check them against a switch or PSE budget and reserve.
Planning model only—no negotiation classes, inrush behavior, per-port limits, cable model or proof that a switch will power a device.
Included
- Every visible input and selected unit
- Reconciled intermediate values and result breakdown
- Reproducible URL state
Not included
- Planning model only—no negotiation classes, inrush behavior, per-port limits, cable model or proof that a switch will power a device.
What this means
Total planned powered-device allocations and check them against a switch or PSE budget and reserve.
Planning model only—no negotiation classes, inrush behavior, per-port limits, cable model or proof that a switch will power a device.
Intermediate values are not rounded; only the localized display formats the result.
Formula & worked example
headroom = budget × (1 − reserve) − total allocation
370 W PSE budget, 20% reserve and three entered device groups
- Inputs
- 24 × 8 W + 4 × 20 W + 2 × 30 W = 332 W allocation
- Calculation
- 370 W × 80% − 332 W = −36 W
The plan exceeds the post-reserve budget by 36 W.
How this calculation works
The calculation follows the formulas, definitions and assumptions explained on this page. The references below support the method and any stated boundaries.
Official sources
- Cisco — Guidelines for Power over Ethernet — Public definitions and technical semantics used by this calculation