Electrical Load Calculator

Q: How do I calculate total electrical load?

Add up all individual loads in watts, then convert to kW (÷1000). Divide by voltage × PF to get amps. Divide kW by PF to get kVA.

Q: What is the difference between connected load and demand load?

Connected load is the total rated power of all equipment. Demand load is the actual load at peak usage — typically 60–80% of connected load, since not all equipment runs simultaneously. Use a demand factor when sizing panels.

Q: How much load can a 200A service handle?

At 240V single phase: 200A × 240V = 48,000W = 48 kW. At 80% continuous load limit: 38,400W = 38.4 kW of continuous load. This is typical for most residential services.

Add multiple electrical loads and calculate the total in watts, kW, kVA, and amps. Useful for panel sizing, generator selection, and electrical audits.

This calculator provides estimates only. Always consult a qualified electrician for real installations.

Add Your Electrical Loads

System Voltage (V)

Power Factor

Total Load

—

Total (Watts)

—

Total (kW)

—

Total Current (A)

—

Apparent Power (kVA)

Formulas

Total Watts = Sum of all (Watts × Quantity)
Total kW = Total Watts ÷ 1000
Total Amps = Total Watts ÷ (Voltage × PF)
Total kVA = Total kW ÷ PF

Practical Notes

Add a 20–25% demand factor: not all loads run simultaneously at full power.
Size your panel/switchboard for 125% of the calculated total (NEC continuous load rule).
For three phase systems, the amps shown is per phase.
Include starting surge current for motors — they draw 3–7× running current at start.
This calculator gives connected load. For demand load, apply your local diversity or demand factor.

Frequently Asked Questions

How do I calculate total electrical load?

List all loads with their watt ratings and quantities. Multiply watts × quantity for each, sum all values for total watts. Convert to kW (÷1000), amps (÷V×PF), and kVA (÷PF).

What is the difference between connected load and demand load?

Connected load is total rated watts of all equipment. Demand load is the realistic peak — typically 60–80% of connected load since not everything runs simultaneously. A 10 kW connected load might have a 7 kW demand load. Always use demand load for panel and cable sizing.

How much load can a 200A service handle?

At 240V single phase: 200A × 240V = 48 kW maximum. At 80% continuous limit: 38.4 kW of continuous loads. This is standard for most US residential services. Larger homes with EV chargers and all-electric heating may need 400A service.