Electrical load calculator
Electrical Load Calculator: Can Your Panel Handle It?
Check whether your home's electrical service has room for an EV charger, hot tub, or other new load. The calculator follows the National Electrical Code's dwelling load method, the standard method licensed electricians use when planning an upgrade.
Free calculator
Estimate your home's electrical load
Enter your service size, home size, and the electric appliances you have. The result updates as you go.
Estimated load after the addition
83 amps
of a 200-amp service (41%)
Likely has room
The estimate stays at or below 80% of your service, which leaves normal headroom.
- Home today
- 67 amps
- Added by new load
- 16 amps
- Heating or cooling (largest)
- 18 amps
The method
How the calculation works
The calculator uses the optional dwelling calculation in Article 220.82 of the National Electrical Code. It adds general lighting and receptacle load at 3 volt-amperes per square foot, 1,500 volt-amperes for each kitchen small-appliance circuit and the laundry circuit, and the nameplate ratings of fixed appliances and the new load.
The first 10,000 volt-amperes of that total count at 100% and the rest at 40%, because not everything runs at once. The largest heating or cooling load is then added: central air or a heat pump at 100%, plus 65% of electric heat strips or an electric furnace. The total divided by 240 volts gives the estimated amps, compared with your main breaker rating.
Appliance figures are typical nameplate ratings. Actual equipment, panel condition, and available breaker spaces can change the answer, which is why an electrician confirms the numbers before any upgrade.
Wondering what an upgrade would cost? See typical prices in the electrical cost estimator.
Common questions
Panel capacity questions, answered
Can a 100-amp panel handle an EV charger?
Sometimes. A 2,000-square-foot home with gas heat and 3-ton central air calculates at about 67 amps today; adding a 40-amp Level 2 charger brings it to about 83 amps, which fits a 100-amp service with little headroom. Homes with electric cooking, drying, or heat often go over. A lower-amp charger or a load-management device can avoid a service upgrade.
Do I need a 200-amp panel?
Not always. Many gas-heated homes run comfortably on 100 or 150 amps, while all-electric homes with heat pumps, electric water heating, and an EV charger usually need 200 amps. If the calculation exceeds your current service, a panel or service upgrade typically costs $3,500–$6,500 in North Texas.
What is an electrical load calculation?
A load calculation estimates the most power a home is likely to draw at once, based on its size, appliances, and heating and cooling. Electricians use it to size a new service or to confirm that an existing panel can take a new circuit such as an EV charger, hot tub, or heat pump.
What if my panel doesn't have enough capacity?
There are three common paths: choose lower-amperage equipment, such as a 32-amp charger setting; install a load-management device that limits the charger when the house is using more power; or upgrade the panel or electrical service. Koryente reviews the panel, wiring, and planned loads before recommending one.
How accurate is this calculator?
It applies the same code method electricians use, with typical appliance ratings, so it is a reliable first check. The final answer depends on the actual nameplate ratings, panel condition, and open breaker spaces, which a licensed electrician confirms on site.
Sources
Ready when you are
Planning an EV charger or a bigger load?
Send the details and a photo of your panel label, and we’ll confirm what your service can handle.