Free tool · CEC 8-200(1)
Free Electrical Load Calculator (Canada)
A free single-dwelling service load calculator built to Canadian Electrical Code Rule 8-200. Give your customers an instant service-size estimate, and embed it free on your own website in one line. Built for Canadian electricians and contractors.
Electrical Load Calculator
Try the calculator your customers would use. Enter a home's details for the recommended service size, in amps, to CEC 8-200.
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: the Canadian Electrical Code, Part I (CSA C22.1), Rule 8-200(1) and Rule 8-110, published by CSA Group, the code's governing authority. Verify against the edition adopted in your province.
Reading the result
When do you need a service or panel upgrade?
The gauge in the result card is the quick read. A service upgrade is usually worth pricing when any of these are true:
- The gauge is yellow or red. Your calculated load is close to your panel rating, or over it.
- You are adding a big load. An EV charger, hot tub, heat pump or electric heat can push a 100 A home to 200 A. Use the "planning to add" toggle to see the effect before you commit.
- The panel is full. No open spaces for new breakers, or you are relying on half-height breakers to squeeze circuits in.
- Breakers trip often. Frequent nuisance trips can be a sign the service is working near its limit.
- You have an older 60 A or 100 A service. Homes that have added modern electric loads over the years often outgrow the original panel.
- The service wire is smaller than the panel. Older conductors are rated below the breaker (CEC Table 4), so the real capacity can be less than the panel number.
If the gauge reads yellow or red, or you are planning a large addition, it is time to have a licensed electrician price the upgrade and file the stamped load calculation.
Before you file
Codes and inspections vary by province.
The Canadian Electrical Code (CSA C22.1) is the national baseline, but every province adopts its own edition, can add amendments, and has its own inspection authority. A figure that passes in one province may need a different treatment in another.
- Ontario. Electrical Safety Authority (ESA).
- British Columbia. Technical Safety BC.
- Alberta. Municipal or accredited-agency inspection under the Safety Codes Act.
- Other provinces. A provincial or municipal electrical inspector.
Always confirm the code edition adopted where you are, and have the final load calculation stamped by a licensed electrician before any permit work.
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, which is 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.
Does electric heating get a demand-factor reduction?
For a single dwelling, no. Rule 8-200(1) adds the electric space-heating load at 100%, or the larger of heating and air conditioning when they are interlocked. The reduced factor some calculators apply, 100% of the first 10 kW then 75% of the rest, comes from Rule 8-202 for row housing and multi-unit buildings, not single dwellings. This calculator uses the single-dwelling method, which is why heating is not discounted here.
Is my breaker rating the same as my real service capacity?
Not always. The panel breaker sets a maximum, but the real limit is the conductor feeding the service, rated per CEC Table 4. Older services in particular can have wire rated below the breaker size, so a 100 A panel may not deliver a full 100 A. This tool sizes the service to the calculated load; a licensed electrician confirms the actual conductor ampacity for the permit.
Can you show a worked example?
Take a 200 m² home with 10 kW of electric heat, 5 kW of air conditioning (interlocked), a 12 kW range, a 7.2 kW EV charger, and 8 kW of other large loads. The basic load is 7000 W (5000 for the first 90 m², plus 1000 for each additional 90 m²). Interlocked heating and A/C count the larger, so 10,000 W. The range is 6000 W. The EV charger is 7200 W at 100%. The other loads over 1500 W are 25% of 8000, or 2000 W, because a range is present. That totals 32,200 W; divided by 240 V that is 134.2 A, so the recommended service is 200 A. These are the calculator's default values, so you can open the breakdown and see each line.
How many amps does a 2,000 sq ft home need?
A 2,000 sq ft home (about 186 m²) with electric heat, a range and typical appliances usually calculates to roughly 100 to 150 A under Rule 8-200, so many need a 200 A service once central air conditioning or an EV charger is added. A gas-heated home the same size can land near the 100 A floor-area minimum. Square footage alone does not decide it, the electric loads do, so enter your real numbers above for the exact figure.
Can a 100 amp panel handle an EV charger?
Sometimes. A 7,200 W Level 2 charger adds about 30 A of calculated load, so whether a 100 A panel fits it depends on how loaded the panel already is. Enter your loads and set the panel to 100 A to see the headroom. If it goes over, an energy management system (EVEMS) can let the charger share capacity and avoid a service upgrade; check the EVEMS box under the car charger to model that.
What size service do I need for a heat pump?
A whole-home electric heat pump draws roughly 7,000 to 10,000 W. On its own it rarely forces an upgrade, but combined with an electric range, water heater and an EV charger it often pushes a 100 A home to 200 A. Because heating and cooling are interlocked, only the larger of the heat pump and the air conditioning counts. Use the "planning to add" toggle to see the effect on your service size.
What is the difference between 100 and 200 amp service?
The number is how much current the service can deliver at once. 100 A (24,000 W at 240 V) suits a smaller home with gas heat and few large electric loads. 200 A (48,000 W) is the common choice for a home with electric heat, central air, an EV charger or a hot tub, and it leaves room to add more later. The calculator recommends the next standard size at or above your calculated load.
Do I need a permit to upgrade my electrical service?
Yes. A service or panel upgrade is permitted, inspected work everywhere in Canada, and the permit needs a load calculation and installation by a licensed electrician. This tool gives you the estimate to plan the job; your electrician files the stamped calculation with your local authority (ESA in Ontario, Technical Safety BC, a municipal or provincial inspector elsewhere).
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.
