Electricity Calculator

  • kW to kWh Calculator
    Convert kilowatts (kW) to kilowatt-hours (kWh) by multiplying power by running time. Free, instant energy calculator with watt-hour output.
  • Electric Charge Calculator (Q = I × t)
    Calculate electric charge (coulombs) from current and time using Q = I × t. Get charge in coulombs, milliamp-hours, and electron count instantly.
  • 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.
  • Solar Battery Storage Size Calculator
    Calculate the solar battery bank size in kWh you need from daily energy use, days of autonomy, depth of discharge, and system efficiency.
  • kWh to Cost Calculator
    Calculate the cost of electricity from kWh used and price per kWh, or from device watts and hours of use. Fast, accurate energy cost estimates.
  • Appliance Electricity Cost Calculator
    Calculate how much an appliance costs to run. Enter watts, hours used, days and your kWh rate to get daily, monthly and yearly electricity cost.
  • Battery Life / Runtime Calculator
    Estimate how long a battery will last from its mAh capacity, the device's current draw in mA, and an efficiency factor. Get runtime in hours and minutes.
  • Electrical Power Calculator
    Calculate real power (kW) from voltage, current and power factor for single-phase or three-phase AC circuits. Fast, accurate electrical power tool.
  • Capacitor Charge Calculator
    Calculate the electric charge stored in a capacitor using Q = C × V. Enter capacitance and voltage to get charge in coulombs plus stored energy.
  • Capacitive Voltage Divider Calculator
    Calculate the output voltage of a resistive voltage divider using Vout = Vin × R2 / (R1 + R2). Also gives divider ratio, current and power.
  • Light Bulb Energy Cost Calculator
    Calculate the yearly, monthly and daily electricity cost of running a light bulb from its wattage, hours used per day and your price per kWh.
  • PC Power Supply (PSU) Wattage Calculator
    Estimate the right PSU wattage for your PC build. Add CPU, GPU, RAM, storage and fans to get a recommended power supply size with 20% headroom.
  • Server Power Consumption Cost Calculator
    Calculate the monthly and yearly electricity cost of running servers 24/7. Enter watts, price per kWh and server count to estimate power expenses.
  • Horsepower to Watts Calculator
    Convert horsepower (HP) to watts (W) instantly. Enter mechanical horsepower and get the equivalent power in watts and kilowatts using W = HP × 745.7.
  • Watts to Horsepower Calculator
    Convert watts (W) to horsepower (HP) instantly. Supports mechanical, metric, and electric horsepower with the formula HP = W / 745.7.
  • Amps to Kilowatts Calculator
    Convert amps (A) to kilowatts (kW) for DC, single-phase and three-phase AC. Enter current, voltage and power factor to get real power instantly.
  • Energy Cost per kWh Calculator
    Find your electricity rate per kWh by dividing your total bill by the energy used. Quick kWh cost calculator with cents-per-kWh output.
  • Watts to kWh Calculator
    Convert watts to kilowatt-hours (kWh) instantly. Enter the power in watts and running time in hours to find total energy use for any appliance.
  • Solar Panel Payback Period Calculator
    Calculate how many years it takes for solar panels to pay for themselves based on system cost, annual energy output, and your electricity price.
  • mAh to Wh Battery Capacity Calculator
    Convert battery capacity from mAh to Wh instantly. Enter milliamp-hours and voltage to get watt-hours and kilowatt-hours for any battery.
  • IoT Sensor Battery Life Calculator
    Estimate how long an IoT sensor or wireless device will run from its battery using capacity (mAh), average current draw (mA), and a usable-capacity derating factor.
  • Solar Panel Payback & ROI Calculator
    Calculate your solar panel payback period and ROI. Enter system cost, annual savings, and lifespan to see break-even years, lifetime savings, and return.
  • Solar Panel Number Calculator
    Calculate how many solar panels you need based on daily kWh energy use, panel wattage, peak sun hours, and system efficiency derating.

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