Electrical calculators
Electrical Load Calculator
Estimate a dwelling’s connected load, preliminary demand load, and current from floor area, appliances, HVAC, voltage, and phase.
Load planning flow
W / VA
Diversity
A
Connected load shows the entered equipment total. Demand load applies a preliminary planning method and should be checked against the local electrical code.
Input Dimensions
Calculation Results
Planning estimate only
Results are based on the values and assumptions entered here. Confirm quantities with current product information and suppliers; use qualified local professionals for structural, safety-critical, permitted, or code-regulated work.
Read the calculator terms and limits →How to Use the Electrical Load Calculator
Enter the living area, the number of small-appliance and laundry circuits, and the nameplate wattage of major equipment. Include water heating, cooking, drying, dishwasher or disposal, heating, cooling, and other continuous loads when they apply. Select the system voltage and phase so the calculator can convert watts to an estimated current.
The result separates total connected load from a preliminary demand load. Connected load represents the entered equipment total. Demand load applies a simplified dwelling planning method to the general and fixed-load subtotal, adds the larger of heating or cooling, and applies a 125% adder to other continuous loads.
Connected Load vs Demand Load
Connected load assumes every entered load operates at the same time. Demand load is a planning estimate that recognizes that some loads are unlikely to run simultaneously. Actual demand calculations depend on the applicable code method, occupancy, equipment ratings, noncoincident loads, motor rules, and local amendments.
A load expected to run for three hours or more may be treated as continuous under common NEC terminology. Schneider Electric’s load-planning guidance describes continuous-load treatment as noncontinuous load plus 125% of continuous load unless a different rule applies. This calculator only applies that adder to the separate “Other Continuous Loads” input, so users can see the assumption rather than hiding it.
Safety and Limitations
This is a preliminary planning estimate, not a service-size approval. Do not use it alone to select a panel, service conductors, feeder, breaker, generator, transformer, or other electrical equipment. A wrong load calculation can cause nuisance trips, overheating, fire, shock, equipment damage, or death.
Final design must verify nameplate data, motor and HVAC rules, demand factors, grounding and bonding, conductor ampacity, voltage drop, equipment ratings, phase balance, local code, utility requirements, and inspection requirements with a qualified electrical professional.
Frequently Asked Questions
What is the difference between connected load and demand load?
Connected load assumes all entered loads are operating together. Demand load applies a preliminary diversity method so the estimate better reflects expected simultaneous demand.
How is the lighting load estimated?
This planning model uses 3 watts per square foot of living area. The applicable code, occupancy, and project jurisdiction may require a different method or unit load.
Why is only the larger heating or cooling load added?
Heating and cooling systems are often noncoincident for preliminary dwelling planning. The actual installation and applicable code determine whether loads can be treated as noncoincident.
Can this calculator determine the final service size?
No. It is a preliminary estimate. Final service, feeder, and panel sizing requires the applicable code method, equipment data, conductor limits, demand rules, local amendments, and qualified review.
Planning context: common dwelling examples use watts per square foot, dedicated appliance inputs, demand diversity, and the larger heating or cooling load. Jurisdiction-specific code methods control the final result.