Service Size Calculator
Quick wizard to recommend main service amperage (100A-400A) based on home type, appliances, and electrical loads.
Major Loads
Recommendation
Load Summary
Simplified estimate per NEC Article 220. For a detailed load calculation, use the Panel Load Calculator.
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How to Use This Calculator
1. Select your home type and square footage. This sets the base load for the calculation.
2. Check off your major electrical loads. Each appliance adds a specific amp load to the calculation. Gas appliances add zero electrical load.
3. Review the recommendation. The calculator shows the minimum service size needed, plus a future-proofed recommendation with 25% headroom.
Frequently Asked Questions
How many amps does my house need?
What is the minimum service size per NEC?
How much does a service upgrade cost?
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