Electrical Load Calculator

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Calculate the total electrical load for your home or building to determine if your electrical panel has sufficient capacity. Enter your major appliances and general lighting/receptacle loads to see the total demand in amps and watts.

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Enter Your Measurements

Results

Total Load

140

amps (240V)

Total Demand

33,625

watts

Recommended Panel Size

150

amps

General Load (demand)

5,625

watts

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Formula

General Load = (Sq Ft × 3W) + 3000 + 1500 | Demand = 3000 + (Remainder × 35%) | Total = Demand + Appliance Loads

How to Use This Calculator

How to Use

  1. 1

    Enter the home square footage for general lighting load calculation.

  2. 2

    Indicate which major electric appliances are present.

  3. 3

    Enter the central AC tonnage (0 if no central AC).

  4. 4

    The calculator uses NEC demand factors to estimate total load.

Frequently Asked Questions

Frequently Asked Questions

What size electrical panel do I need?

Most modern homes need a 200-amp panel. Older homes may have 100 or 150-amp panels. If you are adding an EV charger, electric heat, or a workshop, you may need a 400-amp service or a subpanel.

How many amps does a house use?

A typical 2000 sq ft home uses 100 to 150 amps at peak demand with electric range, dryer, water heater, and central AC. Average sustained usage is much lower, typically 30-50 amps.
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About This Calculator

This calculator uses the formula: General Load = (Sq Ft × 3W) + 3000 + 1500 | Demand = 3000 + (Remainder × 35%) | Total = Demand + Appliance Loads. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.

Built and maintained by the CalcSmart team. Last updated March 2026.

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