What a load calculation tells you
A load calculation adds up everything in the building the way the National Electrical Code requires, then applies the code's demand factors. The result is the minimum service size in amps. It answers the questions every service upgrade, renovation, heat pump or EV charger job starts with: can the existing service carry it, and if not, how big does the new one have to be?
How we calculate it
- Code: the 2025 NYC Electrical Code, based on NEC 2020, in effect since December 21, 2025.
- Standard method (NEC 220 Part III): general lighting at 3 VA per sq ft, small-appliance and laundry circuits, fastened appliances (75% when there are four or more, 220.53), dryers (5,000 VA minimum, 220.54), ranges (Table 220.55), the larger of heating or cooling (220.60) and EV chargers (220.57).
- Optional method for one dwelling (220.82) or three or more units (220.84). It often gives a smaller result. We show both side by side, and the lower permitted result is marked.
- Every apartment feeder is calculated too on 2-family and multifamily buildings.
What we need from you
- Building type, number of units and living area per unit (or your architectural plans and we take the square footage from them)
- Every appliance with its nameplate rating: range or cooktop and ovens, dryer, water heater, dishwasher, mini-splits and heat pumps, EV chargers, pumps
- A photo of the existing panel and meter
Don't know a rating? Pick "Not sure" in the detailed calc and upload the cut sheet or a photo of the label. We never fill a gap with a guess: anything without a rating is flagged until we have it.
Start with the free calc, or send the full project. Load calc, reviewed: $197, fixed price.
Start the detailed calc Free quick calcQuestions
Is the online load calculation free?
Yes. The quick calc on our home page is free with no signup. The reviewed load calculation, checked line by line against your uploads with a signed PDF, is $197.
Which code do you use for NYC?
The 2025 NYC Electrical Code, which is based on NEC 2020 and took effect December 21, 2025. Article 220 sets the load calculation rules.
Standard or optional method: which one is right?
Both are permitted by the NEC for dwellings. The optional method (220.82 for one dwelling, 220.84 for three or more units) often gives a lower result. We calculate both and show which is lower.
Who files the work?
Your licensed electrician reviews and adopts our calculation and files the job. We are consultants, not engineers, and we do not file.