Home Electrical Panel Load Calculator
Calculate your total electrical panel load to see if your panel is overloaded or if you have capacity for new circuits.
Use the NEC load calculation method.
Electrical panel load calculation determines whether your existing service panel can handle your home’s electrical demands. Most residential panels are rated at 100A, 150A, or 200A service. If your calculated load approaches or exceeds the panel rating, you need an upgrade.
NEC simplified residential load calculation (Article 220):
Step 1 — General lighting and receptacle load:
Square footage × 3 watts per sq ft (NEC Article 220.12)
Step 2 — Small appliance circuits: Add 1,500W for each required small appliance circuit (kitchen: 2 circuits minimum = 3,000W)
Step 3 — Laundry circuit: Add 1,500W for one laundry circuit
Step 4 — Large appliances (nameplate wattage): Add actual wattage for each fixed appliance:
- Electric range: 8,000–12,000W (use nameplate)
- Electric dryer: 5,000–6,000W
- Water heater: 3,500–5,500W
- HVAC/heat pump: varies widely
- EV charger (Level 2): 7,200–11,500W
- Pool pump: 750–2,000W
Step 5 — Apply demand factor: The first 10,000W: use at 100% Remaining watts: multiply by 40% (NEC 220.83) — not all loads run simultaneously
Step 6 — Convert to amps:
Total Amps = Total Watts ÷ 240V
Panel sizing guide:
| Service | Suitable For |
|---|---|
| 60A | Very small/older homes — rarely sufficient today |
| 100A | Small homes without electric heat or large appliances |
| 150A | Medium homes, 1–2 large appliances |
| 200A | Most modern homes — standard for new construction |
| 300–400A | Large homes, EV chargers, workshops, pools |
Signs your panel is overloaded:
- Breakers trip frequently
- Lights dim when large appliances start
- Panel feels warm to touch
- Breakers that won’t reset
- Buzzing or burning smell near the panel (emergency — call electrician immediately)
Planning for future loads:
Leave 20–25% headroom in your panel for future additions. If you plan to add an EV charger, pool, or major appliance — calculate future load before adding.