Electrical Panel Load Calculator -- Find Out If Your Panel Can Handle What You Are Adding
Enter the appliances in your home and the new load you want to add. The calculator uses NEC 220.82 residential load calculation methodology to tell you whether your electrical panel has enough capacity -- or whether you need an upgrade first.
This tool is built specifically for Conejo Valley homes. It covers the most common panel sizes found in Thousand Oaks, Agoura Hills, Calabasas, Westlake Village, and Moorpark -- 100-amp, 150-amp, and 200-amp service. Use it before calling DNZ or use it to confirm what your electrician told you.
What your result means
If the calculator shows your panel has available capacity, you likely do not need an upgrade before adding your EV charger or new appliance. A licensed electrician still needs to verify this in person with a full load assessment -- but the calculator gives you a strong starting point.
If the calculator shows your panel is at or over capacity, a panel upgrade is needed before adding the new load. In most Conejo Valley homes built before 1990, this means upgrading from 100-amp service to 200-amp service. DNZ completes panel upgrades and installs the new circuit on the same day in most cases.
The calculator uses NEC 220.82 demand factors, which are the same methodology licensed electricians use to size residential panels. It is not a substitute for a professional load calculation, but it is accurate enough to tell you whether a panel upgrade conversation is worth having before you call.
Important notes on the calculation
- 100-amp panels -- Built before 1987. Cannot safely support a Level 2 EV charger in most homes with normal appliance loads.
- 150-amp panels -- Transitional era. Capacity depends heavily on existing loads. Needs individual assessment.
- 200-amp panels -- Standard modern service. Usually has enough capacity for an EV charger if not already heavily loaded.
- The calculator does not account for utility-side limitations or existing wiring condition. An on-site assessment is still required before any work.
Need a panel upgrade or want to confirm your result?
DNZ Electrical Services performs professional load calculations on every assessment visit. If the calculator flagged a capacity issue, we can confirm it, price the upgrade, and complete the electrical panel upgrade and new circuit installation on the same day in most cases. CA License #1010883. BBB A+. Lifetime workmanship warranty.
The SCE Charge Ready Home rebate covers up to $4,200 of panel upgrade costs for qualifying SCE households. The federal 30C tax credit covers up to $1,000 of EV charger installation costs and expires June 30, 2026.
Cities we serve
Our shop is at 5627 Kanan Rd, Agoura Hills — right in the middle of the Conejo Valley. We cover most of LA County and Ventura County, including the cities below
- Thousand Oaks
- Agoura Hills
- Calabasas
- Westlake Village
- Moorpark
- Oak Park
- Simi Valley
- Van Nuys
- Canoga Park
- Camarillo
- Ventura
- Oxnard
- Malibu
- Woodland Hills
- West Hills
- Chatsworth
- Northridge
- Encino
Not sure if we cover your area? Check our Service Area Page or Call or Text 818-514-1417. We'll tell you straight
Frequently asked questions
Q: How accurate is this electrical panel load calculator?
The calculator uses NEC 220.82 residential load calculation methodology, which is the standard code-based approach licensed electricians use to size electrical panels. It is accurate as an initial screening tool. It is not a substitute for an on-site assessment by a licensed electrician, which accounts for wiring condition, breaker quality, utility-side limitations, and other factors the calculator cannot see. DNZ performs full load calculations on every assessment visit at no additional charge. CA License #1010883. Call 818-514-1417.
Q: What panel size do I need for an EV charger?
In most cases, a 200-amp panel with available capacity is sufficient for a Level 2 EV charger Installation . A Level 2 charger at 48 amps requires a dedicated 60-amp circuit. On a 100-amp panel already loaded with normal household appliances, that leaves insufficient headroom and a panel upgrade is needed. The calculator above will show you whether your specific panel and appliance combination has enough capacity. If you need a panel upgrade, DNZ completes the upgrade and installs the EV charger circuit on the same day in most cases.
Q: My Thousand Oaks home was built in 1979 -- do I need a panel upgrade for an EV charger?
Probably yes. Most Conejo Valley homes built before 1987 have 100-amp panels. When combined with a central air conditioner, electric dryer, oven, and other standard loads, a 100-amp panel typically does not have enough remaining capacity for a dedicated 60-amp EV charger circuit. Use the calculator above to check, then call DNZ at 818-514-1417 for a same-day assessment. The SCE Charge Ready Home rebate covers up to $4,200 of panel upgrade costs for qualifying households.
Q: What is NEC 220.82 and why does the calculator use it?
NEC 220.82 is the section of the National Electrical Code that governs residential load calculations. It applies demand factors to each load category to account for the statistical reality that not all appliances run simultaneously at full capacity. A licensed electrician uses NEC 220.82 to calculate the actual demand your home places on the panel and compare it to the panel's rated capacity. This calculator applies the same methodology so you can get a reliable estimate before calling an electrician.