NEC 2023 load calculations you can hand to an inspector
The Contractor Load Calculator runs the full Article 220 standard method and the 220.82 optional method on the same dwelling, shows every line item with its clause, and exports a permit-ready packet: cover sheet, load calculation and panel schedule in one PDF.
Pro is $15/month after the trial. The load calculator and panel schedule builder require a Pro account. The sample permit packet (NEC Annex D Example D2(a) for a fictional contractor, with its panel schedule) opens without an account.
Avoid the service upgrade (NEC 2026, 120.7)
Power control systems are in the 2026 calculation. Annex D Example D15(a): a 29,040 VA / 121 A dwelling on a 100 A service adds a 50 A charger behind a PCS that can switch it off, and the calculated load becomes 17,040 VA / 71 A. The calculator's "Will it fit?" panel applies 120.7 to any 2026 result, picks the controlled loads from what you entered, and prints the section in the packet.
Standard and optional methods side by side
Run Article 220 Part III and the 220.82 optional method on the same dwelling and see which one sizes the service smaller, with the difference in VA and amps. Most calculators only do one.
Every line item carries its clause
Table 220.45 lighting demand, 220.53 fixed appliances, Table 220.54 dryers, Table 220.55 cooking with Notes 1 to 3, 220.60 noncoincident loads, 430.24 largest motor. The basis is written out on each row.
Permit-ready packet
One PDF per job: a cover sheet with your company, license and logo, the customer and permit details, the load calculation with per-clause line items, method comparison and service sizing, and the panel schedule, with the reviewer disclaimer on every page.
Saved scenarios and projects
Keep each job’s calculation, compare alternatives for the same property, and reload a scenario when the scope changes.
Panel schedules
Turn a saved calculation into a balanced 120/240 V panel schedule: one circuit per load, leg balancing with the imbalance shown, spares, existing circuits and tandem breakers, printed as its own section of the permit packet.
Want the clause list, the scope limits and the Annex D verification table? Read the calculation methodology
What the calculator covers
Inputs match how a dwelling is actually described on a job.
Dwelling
Floor area per 220.41 including the attached garage, small-appliance and laundry circuits, service voltage.
Appliances
Fastened-in-place appliances by nameplate, ranges and ovens by rating with correct Table 220.55 column selection, dryers with the 5,000 VA floor.
Heating, cooling, motors
Resistance heat by controlled units, heat pumps with supplemental heat and interlock, A/C nameplate, largest-motor adder, continuous loads.
Free tools for the truck
Quick answers for customers, no login.
Generator Cost Calculator
Calculate fuel costs for whole home generators and compare fuel types.
- Multiple fuel types
- Load level estimates
- Daily & weekly costs
- Fuel type comparison
Home Electrical Load Estimator
Find out how much electrical service your home needs and what size standby generator would cover it.
- Simplified NEC 220.82 optional method
- Calculated load in amps
- Minimum service size
- Standby generator sizing
Common questions
Each one worked through the same verified engine as the calculators, with the inputs and the result shown.
- Load calculationsWhat does a 200 A service load calculation look like, line by line?A complete NEC 2023 Article 220 standard-method calculation for a 2,400 ft² all-electric house with a heat pump and well pump, every line item with its clause, plus the 220.82 optional method on the same house.
- EV chargingHow much does an EV charger add to a load calculation, by charger amps?Standard-method results for one 2,000 ft² house with a 16, 24, 32, 40, 48 and 80 A EV charger under NEC 2023 (220.57 floor plus the 125% continuous adder) and NEC 2026 (120.57 nameplate, no adder).
- PanelsAre tandem breakers allowed, and how many can a panel take?Yes, where the panelboard is listed for them. What the CTL limit and the "30/40" on a panel label mean, and a panel schedule engine placing 36 circuits in a 30-space, 40-circuit panel versus a 30/30 panel.
- PanelsWhat is a panel schedule, and what has to be on it?A panel schedule is the circuit directory for a panelboard, printed as a two-column table. What each column means, the NEC 408.4 requirement behind it, and the schedule from our sample permit packet with its leg totals.
- NEC editionsWhat changed in dwelling load calculations between NEC 2023 and NEC 2026?One 2,200 ft² house calculated under both editions and both methods: Article 220 becomes 120, lighting drops to 2 VA/ft², the 125% continuous adder goes, EVSE moves to nameplate, and the optional method’s tiers change.
Try it on your next service upgrade
30 days free, cancel anytime during the trial.