Free tool · Canada
Electrical service load calculator
Size a single-dwelling service to Canadian Electrical Code Rule 8-200 in seconds. Enter your home’s details and get the calculated load and recommended service size. No signup, works on your phone.
How it works
The CEC 8-200 method, step by step.
- Basic load. 5000 W for the first 90 m² of living area, plus 1000 W for each additional 90 m² (or part). Living area is 100% of floors above grade plus 75% of a heated basement (Rule 8-110).
- Heating or cooling. The larger of electric space heating or air conditioning when interlocked; both if they can run together.
- Electric range. 6000 W, plus 40% of any amount over 12 kW.
- Water heating, EV, pools/spas. Tankless water heaters, EV chargers, pools, hot tubs and spas count at 100%.
- Other loads over 1500 W. 25% of the combined rating when a range is present; if no range, 100% of the first 6000 W plus 25% of the rest.
- Floor-area minimum. The result can’t be less than 24,000 W (100 A) for homes 80 m² or larger, or 14,400 W (60 A) below that.
- Service size. Calculated watts ÷ 240 V = amps, rounded up to the next standard service (100, 125, 200 or 400 A).
Method: Canadian Electrical Code, Part I, Rule 8-200(1) and Rule 8-110. Verify against the edition adopted in your province.
Questions
Load calculation, answered.
How is a residential electrical service size calculated in Canada?
Under Canadian Electrical Code Rule 8-200(1), a single dwelling’s service is the greater of two figures: (a) an itemised load — 5000 W for the first 90 m² of living area plus 1000 W per additional 90 m², plus heating or air conditioning, the range, water heating, EV charging and other large loads with their demand factors — or (b) a floor-area minimum of 24,000 W (100 A) for homes 80 m² or larger. The calculated watts are divided by 240 V to get amps, then rounded up to the next standard service size.
Do electric heating and air conditioning both count?
Only the larger of the two when they are interlocked so they cannot run at the same time (the usual case). If they can operate simultaneously, both are added. Leave the interlock toggle on unless your equipment can run heat and A/C together.
How is the electric range counted?
A single range counts as 6000 W, plus 40% of any amount over 12 kW. So a 12 kW range is 6000 W; a 14 kW range is 6000 + 40% × 2000 = 6800 W.
Is a tankless water heater treated differently than a tank?
Yes. Tankless (on-demand) water heaters, pools, hot tubs and spas count at 100%. A standard storage-tank water heater goes in the "other loads over 1500 W" group, which is demand-factored at 25% when an electric range is present.
Is this an official calculation?
No. This is a fast estimate to CEC 8-200(1) to help you plan a service or panel upgrade. The final calculation must be done and stamped by a licensed electrician and verified against your local authority having jurisdiction (ESA in Ontario, Technical Safety BC, Alberta Municipal Affairs, etc.) and the code edition adopted in your province.
Planning a panel or service upgrade? See the electrician benchmarks for what panel upgrades, EV chargers and generators actually cost, or get a free marketing audit for your electrical business.
