Electrical Load Calculator
Add your electrical circuits to calculate total panel load in amps and kilowatts. Useful for panel sizing, generator sizing, and evaluating whether your service is large enough.
Circuits
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Total load (A)
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Total load (kW)
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% of panel capacity
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Available headroom
How to Calculate Electrical Load
Total electrical load is the sum of all circuit loads connected to the panel. The NEC uses a demand factor approach for residential calculations, recognising that not all loads operate simultaneously. For a conservative panel sizing estimate, this calculator totals all listed loads at full value.
NEC Demand Factors (Residential — Article 220)
| Load type | Demand factor |
|---|---|
| First 3,000 VA of lighting | 100% |
| Next 117,000 VA of lighting | 35% |
| Over 120,000 VA | 25% |
| Kitchen circuits (2 required) | 100% of 1,500 VA each |
| Laundry circuit | 100% of 1,500 VA |
| Dryer | 100% (or 5,000 W minimum) |
| Range / cooktop | 8,000 W for up to 12 kW unit |
| AC vs. heat | Largest of heating or cooling |
For simple add-it-up load calculations, ignore demand factors and use the full connected load — this gives a conservative (safe) result.
Common Residential Circuit Loads
| Circuit | Typical load |
|---|---|
| General lighting (15 A) | 1,440 W (80% of 1,800 W) |
| Small appliance (20 A) | 1,500 W |
| Kitchen appliance (20 A) | 1,500 W |
| Electric dryer (30 A, 240 V) | 5,000–7,200 W |
| Electric range (50 A, 240 V) | 8,000–12,000 W |
| Central AC (240 V) | 3,500–6,000 W |
| Electric water heater (30 A, 240 V) | 4,500 W |
| EV charger Level 2 (40 A, 240 V) | 7,680 W |
| Hot tub / spa (50–60 A, 240 V) | 6,000–12,000 W |
Panel Sizing Guide
| House size | Minimum panel | Recommended |
|---|---|---|
| Small apartment / older home | 100 A | 150 A |
| Average home (no EV, no electric range) | 150 A | 200 A |
| Modern home (electric appliances) | 200 A | 200–400 A |
| Home with EV charger + electric range | 200 A | 200–400 A |
| Home with solar + battery + EV | 200–400 A | 400 A |
Frequently Asked Questions
How do I know if my panel is overloaded?
If breakers trip frequently under normal load, outlets and switches feel warm, lights dim when appliances start, or your panel is a recalled brand (Federal Pacific, Zinsco), have a licensed electrician evaluate your service. A properly loaded panel should operate at 80% or less of its rated capacity for continuous loads.
Can I add a circuit to a full panel?
A full panel has no open breaker slots, but an electrician can install a tandem (dual) breaker in some slots, or install a sub-panel fed from the main panel to add capacity. If your panel is near or over 80% load, the practical solution is a panel upgrade.
How many amps does a 200 A panel actually support?
A 200 A main breaker permits a maximum of 200 A, but NEC 80% rule means continuous loads should not exceed 160 A (200 × 0.8). Non-continuous loads (short-duration) can use the full 200 A capacity.
