calctricFrom input to answer.
- Set the region to Canada and open All Tools → House Load.
- Enter the living areas and choose their units. The supported single-dwelling calculation assumes a 120/240 V service.
- Work through cooking, heating/cooling, EV and other load categories. Use nameplate data and the actual equipment arrangement.
- Read demand, minimum required capacity, the suggested next main rating and the calculation breakdown.
WORKED EXAMPLE
A single-dwelling example
Enter
Use 140 m² above-ground living area, no eligible basement area, a 12 kW range, 4 kW cooling, 7.68 kW EV load, 5 kW dryer, 4.5 kW storage water heater and 240 V.
Read the result
The model result is 26,055 W, about 108.6 A. The next displayed main rating is 125 A for that example. Recheck the full input list before comparing this number with another project.
Get more from it.
- Area is an input to demand, not simply the property listing’s floor area in any units.
- Equipment duty and qualifying interlocks can affect treatment. Do not assume two loads are non-coincident.
Know the limits.
- Supported CEC 2024 single-dwelling scope; not a multi-unit or commercial service calculation.
- The result does not size service conductors or apply every provincial amendment. Ontario-specific Table 39 conductor sizing is not included.
- The service-demand conversion uses 240 V. It is not a general service-voltage selector.
Verify the inputs, applicable local requirements and real conditions. The app is a calculation aid and can contain errors. See our terms and safety disclaimer.
Common questions.
Is the suggested main rating a design approval?
No. Review the actual installation, service equipment, supply requirements and applicable local rules.