Electricity Calculator

  • Volts to Amps Calculator
    Convert volts to amps using power (I = P/V) or resistance (I = V/R). Free electrical calculator for current in amperes from voltage.
  • Watts to Volts Calculator
    Convert watts to volts instantly. Enter power in watts and current in amps to find voltage using V = P / I. Free online electrical calculator.
  • VinFast Home Charger Electricity Cost Calculator
    Estimate the monthly and annual electricity cost of charging your VinFast EV at home based on miles driven, efficiency, and your kWh rate.
  • Monthly Electricity Bill Estimator
    Estimate your monthly electricity bill from kWh usage, your rate per kWh, and any fixed service charge. See monthly and annual cost instantly.
  • Volts, Amps, Watts, Ohms Calculator
    Ohm's law calculator: enter any two of voltage, current, resistance or power and instantly compute the other two using V=IR, P=VI, P=IĀ²R, P=VĀ²/R.
  • Solar Panel System Size Calculator
    Estimate the solar PV system size (kW) and number of panels you need from your daily energy use, peak sun hours, performance ratio and panel wattage.
  • Solar System Size Calculator
    Estimate the solar PV system size (kW) you need from your monthly kWh use, peak sun hours and a system derate factor. Free, instant solar sizing.
  • Whole Home Electricity Bill Calculator
    Estimate your whole-home electricity bill by adding up each device's kWh, then applying your per-kWh rate and fixed fee. Works in any currency.
  • Watts, Volts, Amps & Ohms Calculator
    Solve for voltage, current, resistance or power from any two known values using Ohm's Law (V=IR) and the power equations P=VI, P=IĀ²R, P=VĀ²/R.
  • Appliance Energy Cost Calculator
    Calculate how much an appliance costs to run per day, month, and year from its wattage, hours of use, days per week, and your electricity rate per kWh.
  • Electrical Energy Calculator
    Calculate electrical energy from power and time with E = PĀ·t. Enter watts or kilowatts and seconds, minutes or hours to get joules, Wh and kWh.
  • Inverter Size Calculator
    Calculate the right inverter size in VA from your total load in watts and power factor, with a safety margin for surge headroom and reliable operation.
  • Speaker Impedance Calculator
    Calculate total speaker impedance for series or parallel wiring. Enter up to 4 speaker impedances in ohms to find the combined load on your amplifier.
  • Watts to Amps Calculator (Three Phase)
    Convert watts to amps for three-phase AC circuits. Enter power, line-to-line voltage and power factor to get line current in amperes instantly.
  • Electricity Carbon Footprint Calculator
    Calculate the COā‚‚ carbon footprint of your electricity use from kWh and your grid emission factor (kg COā‚‚/kWh), per period and total.
  • Three-Phase Power Calculator
    Calculate three-phase active, apparent and reactive power from line voltage, line current and power factor using P = āˆš3Ā·VĀ·IĀ·cos Ļ†.
  • VinFast Monthly Charging Budget Calculator
    Estimate your VinFast EV's monthly home-charging cost from miles driven, efficiency (mi/kWh), and your electricity rate. Includes yearly and per-mile costs.
  • VinFast VF3 Charging Cost Calculator
    Estimate the cost to charge a VinFast VF3 EV from your start to target state of charge using battery size, charging efficiency, and your electricity rate.
  • Lighting kWh Usage Calculator
    Calculate the kWh energy used by your lighting and its cost. Enter bulbs, watts, hours per day and days to estimate consumption and electricity bills.
  • AC Power Calculator
    Calculate real (W), reactive (VAR) and apparent (VA) power in single-phase AC circuits from voltage, current and power factor. Free online tool.
  • Maximum Lights per Circuit Calculator
    Find how many light fixtures you can safely put on a circuit. Enter voltage, breaker amps and watts per fixture to get the max count at the 80% rule.
  • Lighting Watts to Amps Calculator
    Convert lighting watts to amps instantly. Enter total fixture wattage, voltage, and power factor to find the current draw for sizing circuits and breakers.
  • Conduit Fill Calculator (NEC)
    Calculate conduit fill percentage and check it against US NEC limits (53% for 1 wire, 31% for 2, 40% for 3+ wires) using wire and conduit areas.
  • Electricity Usage Monthly Cost Calculator
    Estimate the monthly electricity cost of any appliance from its wattage, daily hours of use, days per month, and your rate per kWh.

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