Electrical Load Calculator
A free electrical load calculator that runs a residential load calculation by the NEC Article 220 standard method — enter the dwelling's square footage, appliances, dryer, range, HVAC, and EV charger, and get a permit-ready worksheet with the service size in amps. No signup, nothing to install.
General load
Fixed appliances
Fastened-in-place appliances like a water heater, dishwasher, or disposal. Exclude the range, dryer, A/C, space heat, and EVSE — those are entered below. Four or more here earns a 75% demand factor (NEC 220.53).
Range, dryer, HVAC & EV
Residential service load calculation
| Load component | NEC | VA |
|---|---|---|
| General lighting & receptacles (2,000 sq ft × 3 VA) | 220.12 | 6,000 |
| Small-appliance branch circuits (2 × 1500 VA) | 220.52(A) | 3,000 |
| Laundry branch circuit (1 × 1500 VA) | 220.52(B) | 1,500 |
| General load after demand factors10,500 VA total → first 3000 @ 100% + next @ 35% + remainder @ 25% | 220.42 | 5,625 |
| Fixed / fastened-in-place appliances5,700 VA nameplate × 100% | 220.50 | 5,700 |
| Electric clothes dryer (greater of 5000 VA or nameplate) | 220.54 | 5,000 |
| Electric range / oven (Table 220.55, Col. C) | 220.55 | 8,000 |
| Larger of heating or air conditioning (A/C)heat 0 VA vs A/C 4,800 VA — omit the smaller | 220.60 | 4,800 |
| EV charger / EVSE (continuous × 125%)7,680 VA × 125% | 625.42 | 9,600 |
| Other large 240V loads (pool, hot tub, etc.) | 220.14 | 0 |
| Total calculated load | 38,725 VA | |
Estimate — NEC Article 220 standard method at 240V. Verify before use.
Tip: in the print dialog, choose "Save as PDF" as the destination to download the worksheet.
Disclaimer: This electrical load calculator produces an estimate using the NEC Article 220 standard method and is not a substitute for professional design. Verify every result against the current edition of the NEC and your local amendments, and have a licensed electrician or the authority having jurisdiction (AHJ) confirm the service size before any work or permit submission.
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How to calculate a residential electrical load (NEC Article 220)
A residential load calculation by the NEC Article 220 standard method starts with the general lighting load — 3 VA for every square foot of living area — then adds the two small-appliance branch circuits and the laundry circuit at 1500 VA each. That combined general load gets the NEC 220.42 demand factors: the first 3000 VA at 100%, the next portion up to 120,000 VA at 35%, and any remainder at 25%.
On top of the demand-adjusted general load you add the fixed appliances (with a 75% factor when four or more are present, per 220.53), the clothes dryer at the greater of 5000 VA or nameplate (220.54), the range from Table 220.55, and the larger of heating or air conditioning — never both — under 220.60. An EV charger is a continuous load, so its nameplate is multiplied by 125%. Dividing the total volt-amperes by 240 gives the demand in amps, and this electrical load calculator rounds up to the next standard service size so your worksheet is ready for the panel, EV, or service job.
Frequently asked questions
- What size electrical service do I need?
- Divide your total calculated load in volt-amperes by 240 to get the demand in amps, then round up to the next standard service size — typically 100, 125, 150, 200, 225, or 400 amps. Most modern single-family homes with electric range, dryer, and HVAC land on a 200-amp service, but a small dwelling can be fine on 100 or 125 amps. This electrical load calculator picks the next standard size at or above your calculated amps.
- What is the NEC standard method for a residential load calculation?
- The NEC Article 220 standard method (Part III) adds a 3 VA per square foot general lighting load, the small-appliance and laundry circuits, then applies the 220.42 demand factors. Fixed appliances, the dryer (220.54), the range (Table 220.55), the larger of heating or air conditioning (220.60), and any EV or other large loads are added at their own demand factors to reach the total VA.
- How do the NEC 220.42 demand factors work?
- After totaling the general lighting, small-appliance, and laundry loads, NEC 220.42 lets you apply demand factors: the first 3000 VA counts at 100 percent, the portion from 3001 to 120,000 VA counts at 35 percent, and anything above 120,000 VA counts at 25 percent. This reflects that not every receptacle and light runs at once.
- Does this electrical load calculator replace a licensed electrician?
- No. It is an estimate produced by the NEC 220 standard method and is not a substitute for professional design. Always verify the result against the current NEC and your local amendments, and have a licensed electrician or the authority having jurisdiction confirm the service size before any work or permit submission.