Panel Load Calculator (Service Panel Capacity)

A panel is a promise of capacity. Too many circuits, or bursts of simultaneous draw, push it past its rating and the main breaker starts deciding when you work. The fix is to know the demand before the trip.

Panel Load Calculator totals connected load by category, applies demand factors, converts to kVA and compares with the panel or service rating — flagging overloads and showing how much headroom remains.

Everything runs in the browser; nothing is uploaded.

• Category inputs: Lighting, sockets, appliances, HVAC, motors, other.
• Demand factors: Typical values pre-filled, all editable.
• Panel rating: Enter amperage and voltage or kVA directly.
• Connected vs demand: Both totals shown separately.
• Continuous share: 125% note for continuous circuits.
• Overload verdict: Utilisation and a clear recommendation.
• Export: Copy or download the schedule as text, CSV or JSON.

1. Enter each category load in kW.
2. Adjust the demand factor where usage differs from the default.
3. Enter the panel rating — amps and voltage.
4. Read the connected and demand totals side by side.
5. Judge the utilisation against the 80% and 100% guides.
6. Export the panel schedule if needed.

Example 1 — Commercial board. 20 kW lighting at 0.5, 15 kW sockets at 0.4, 30 kW HVAC at 1.0: demand about 46 kW, needs a panel at or above about 55 kVA.

Example 2 — Overload. 144 kVA rated panel showing 160 kVA demand — the main breaker will trip under load.

Example 3 — Headroom. A 23 kVA single-phase panel at 14 kVA demand has room for about two more 4 kW circuits.

Example 4 — Continuous. 30 kW of continuous heating counts as 37.5 kW for feeder and case sizing.

• See the real load: Demand, not the nameplate fantasy.
• Capacity check: Utilisation against the actual panel rating.
• Editable factors: Tune to the building habit, not a fixed rule.
• Schedule ready: The export is a workable panel note.
• Free and private: No uploads, no accounts, no logging.