{"id":"electrical-load-calculator","name":"Home Electrical Load Calculator","shortName":"Electrical Load","canonicalUrl":"https://calcurhome.com/calculators/electrical-load-calculator","catalogUrl":"https://calcurhome.com/api/calculators","category":{"id":"home-energy","name":"Home energy & comfort","url":"https://calcurhome.com/calculators/category/home-energy"},"language":"en-US","audience":"US homeowners, DIYers and home-project planners","primaryKeyword":"electrical load calculator","secondaryKeywords":["electric load calculator","home electrical load calculation","watts to amps load calculator","continuous load calculator","single phase electrical load calculator"],"description":"Combine continuous and noncontinuous watts, an editable demand factor and planning reserve into single-phase design watts and current for review.","directAnswer":"Enter continuous watts, noncontinuous watts, an applicable demand percentage, system voltage, and an optional planning reserve. The calculator applies 125% to the continuous subtotal, adds the noncontinuous subtotal, then applies the entered factors and converts single-phase watts to amperes. It is not a dwelling service, feeder, panel, breaker, or permit calculation.","inputs":[{"key":"continuousWatts","label":"Continuous-load subtotal","unit":"W","defaultValue":3000,"min":0,"max":10000000,"step":10,"help":"Include only loads properly classified as continuous under the adopted rules."},{"key":"noncontinuousWatts","label":"Noncontinuous-load subtotal","unit":"W","defaultValue":4500,"min":0,"max":10000000,"step":10},{"key":"demandFactor","label":"Applicable demand factor","unit":"%","defaultValue":100,"min":1,"max":100,"step":1,"help":"Leave at 100% unless a qualified calculation establishes a permitted demand factor for this subtotal."},{"key":"voltage","label":"Single-phase voltage","unit":"V","defaultValue":240,"min":1,"max":1000,"step":1},{"key":"planningReserve","label":"Optional planning reserve","unit":"%","defaultValue":20,"min":0,"max":100,"step":1,"help":"A comparison allowance only; it is not a substitute for required load or service calculations."}],"formula":{"title":"Continuous and noncontinuous single-phase load subtotal","expression":"Planning watts = ((continuous W × 1.25) + noncontinuous W) × demand factor × (1 + reserve); planning amps = planning watts ÷ voltage.","explanation":"The calculator makes each arithmetic step visible: a 125% factor is applied to the subtotal the user has classified as continuous, other watts are added, and user-entered demand and reserve percentages follow. Complete code load calculations contain classifications and methods this simplified subtotal cannot determine."},"measurementGuide":["Build a nameplate schedule listing every fixed appliance, HVAC unit, motor, receptacle allowance, lighting load, charger, and other proposed load.","Separate loads only after a qualified reviewer confirms which are continuous, noncontinuous, intermittent, noncoincident, or eligible for a demand method.","Use actual equipment voltage and input ratings; do not substitute output capacity, horsepower, cooling tons, or marketing labels for electrical input.","Document existing and proposed loads separately so additions can be compared with the approved service, feeder, panel, and utility conditions."],"buyingTips":["Have a qualified electrician perform the complete adopted-code load calculation before choosing service, feeder, panel, conductor, breaker, transfer, or EV equipment.","Do not use an arbitrary demand percentage simply to reduce the result; keep 100% unless a permitted method supports another value.","Coordinate large loads with utility service limits, equipment specifications, available fault current, and any energy-management system requirements.","Keep the equipment schedule, calculation method, adopted code edition, local amendments, utility correspondence, and approved documents together."],"workedExample":{"title":"A transparent preliminary single-phase subtotal","scenario":"A planning worksheet contains 3,000 watts correctly classified as continuous and 4,500 noncontinuous watts. It uses a 100% demand factor, 240 volts, and a 20% comparison reserve.","result":"The continuous subtotal becomes 3,750 watts, the connected design subtotal is 8,250 watts, and the reserve raises the comparison subtotal to 9,900 watts, or about 41.3 amperes at 240 volts."},"commonQuestions":[{"question":"Can this calculator size my home's electrical service?","answer":"No. Residential service and feeder calculations apply detailed rules to floor area, appliance circuits, cooking, laundry, HVAC, motors, EV charging, demand factors, and other conditions. This tool only organizes two user-classified watt subtotals for professional review."},{"question":"What counts as a continuous electrical load?","answer":"That is a code classification based on how the maximum current is expected to continue, not simply whether equipment is plugged in often. A qualified electrician should classify each load under the adopted code before you place its watts in the continuous field."},{"question":"Why is there a demand-factor input?","answer":"Some approved load-calculation methods permit specific demand treatment for defined load groups. The field keeps that assumption visible, but it does not determine eligibility. Use 100% unless the adopted method and a qualified reviewer support a different value."},{"question":"Is the planning reserve required by electrical code?","answer":"The reserve field is an optional scenario comparison, not a universal code factor. Future-load planning, spaces, capacity, energy management, and expansion requirements must be resolved from the project scope, equipment, utility rules, adopted code, and professional design."}],"sources":[{"name":"NFPA 70 — National Electrical Code development","url":"https://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70","note":"Official NFPA information for the model electrical code used by adopting jurisdictions; the locally adopted edition and amendments control an installation."},{"name":"Southwire — Building Wire Selector","url":"https://www.southwire.com/calculators/re3%E2%84%A2-building-wire-selector-calculator","note":"Manufacturer reference emphasizing that final cable selection must account for installation conditions, current codes, a licensed electrician, and the authority having jurisdiction."},{"name":"OSHA — Wiring methods, components, and equipment","url":"https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.405","note":"Federal construction-safety requirements for wiring methods, raceways, enclosures, grounding continuity, flexible cords, and temporary installations."}],"defaultCalculation":{"inputs":{"continuousWatts":3000,"noncontinuousWatts":4500,"demandFactor":100,"voltage":240,"planningReserve":20},"result":{"value":"41.3","unit":"A at entered voltage","label":"Preliminary single-phase planning current","lines":[{"label":"Continuous load at 125%","value":"3,750 W"},{"label":"Connected design subtotal","value":"8,250 W"},{"label":"After 100% demand factor","value":"8,250 W"},{"label":"After 20% reserve","value":"9,900 W"}],"summary":"3,000 continuous watts become 3,750 watts at 125%. Adding 4,500 noncontinuous watts and the entered demand and reserve factors produces 9,900 planning watts, or 41.3 amperes at 240 volts.","note":"This transparent subtotal does not perform the complete NEC dwelling, feeder, service, motor, HVAC, appliance, neutral, fault, panel, or local load calculation. Use it to organize inputs for a qualified electrician or engineer."}},"reviewedOn":"2026-08-03","disclaimer":"Planning estimate only. Verify product coverage, supplier rounding, local codes and structural requirements before purchase or construction."}