Dwelling Load Calculator
Estimate a one-family dwelling service load using the 2026 NEC standard method or optional method.
Load details
The optional method requires a qualifying 100 A or larger service.
Use qualifying dwelling floor area under the adopted code.
Count qualifying ¼ hp or 500 VA and larger appliances. Exclude ranges, dryers, HVAC, and EVSE.
Do not repeat the largest motor entered below.
Calculated at 240 V. This is a load estimate, not a service or conductor selection.
About this calculator
This worksheet estimates a one-family dwelling calculated load using either the standard method or the optional method. It shows load categories separately so you can review what contributes to the result.
Use actual equipment nameplates and qualifying floor area. A service-load calculation does not confirm the selected service, conductors, or overcurrent protection are suitable.
Method and assumptions
The standard method uses 3 VA per square foot for general lighting and applies the dwelling demand tiers. Small-appliance and laundry circuits add 1,500 VA each. Eligible fixed appliances, cooking equipment, clothes dryers, EVSE, HVAC, motor loads, and other specific loads are handled in their applicable categories.
The optional method uses 2 VA per square foot plus 1,500 VA for each small-appliance and laundry circuit before applying 100% to the first 8 kVA and 40% to the remainder. It is restricted to qualifying one-family services rated 100 A or more. EVSE is added separately. Heating and cooling use the applicable noncoincident or demand-factor provisions represented by the selected inputs.
This calculator covers common input categories and is not a substitute for all Article 120 rules, exceptions, load-management provisions, equipment instructions, or local amendments. Confirm the exact calculation for the installation.
FAQs
Which method should I use?
Use the standard method unless the dwelling and service meet the optional-method conditions. The optional method is limited to qualifying one-family dwelling services rated 100 A or more. Confirm eligibility and the locally adopted NEC.
What should be included in eligible fixed appliances?
Enter qualifying fixed-in-place loads such as a water heater, dishwasher, or disposal. Do not repeat cooking equipment, clothes dryers, HVAC, or EVSE in that group.
How does this handle heating and cooling?
The calculator uses the larger heating or cooling load when the systems cannot operate simultaneously. If the systems can run together, select that condition so both loads are included. The optional method applies its listed demand conditions to the supported heating categories.
Does this tell me what service rating or conductor size to install?
No. It estimates the calculated load and current only. It does not size service conductors, overcurrent protection, grounding, or equipment.
Sources
- 2026 NFPA 70 (NEC), Article 120, dwelling service and feeder load calculations, including the applicable standard and optional methods.
- Verify the edition adopted by the authority having jurisdiction and current equipment nameplate data.