Free electrical calculators for voltage, current, resistance, wire sizing, and Ohm’s Law — built for electricians, students, and DIYers.
Overview Formula 01What this calculator tells you This calculator estimates the total electrical service load of a single-family home using the optional calculation in NFPA 70, the National Electrical Code (Article 220.82). Enter your living area, the number of small-appliance and laundry circuits, the nameplate volt-amps of your fixed appliances, and your heating and cooling … Read more
Overview Formula 01What this calculator tells you This calculator checks whether your cables fit inside a cable tray within the limits of Article 392 of the National Electrical Code (NFPA 70). Choose the tray type and inside width, enter the overall outside diameter of your cable and how many you are running, and it returns … Read more
Overview Formula 01What this calculator tells you This calculator checks whether your conductors fit inside a raceway within the limits of the National Electrical Code (NFPA 70). Pick the conduit type and trade size, the conductor insulation and size, how many conductors you are running, and whether it is a standard run or a short … Read more
Overview Formula 01What this calculator estimates This solar panel sizing calculator turns your household electricity use into the four numbers that actually matter when planning a rooftop system: the system size in kilowatts (kW), the number of panels, the roof area they occupy, and the expected annual generation in kWh. Instead of a bare wattage … Read more
