Electricity Calculator

  • 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.
  • kVA Calculator
    Calculate apparent power in kVA from voltage and current for single-phase and three-phase circuits. Free, instant kVA calculator with formula.
  • Generator Size Calculator
    Calculate the right generator size in watts. Add running watts plus the largest starting surge, with a safety margin, to size your generator correctly.
  • Device Power Consumption Cost Calculator
    Calculate how much electricity a device costs to run. Enter watts, hours per day, days and your price per kWh to get total and daily running cost.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • LED Series-Parallel Array Calculator
    Calculate the series resistor, voltage drops, current and power for an LED array with multiple parallel strings of LEDs in series.
  • Watts to Lumens Calculator
    Convert watts to lumens using luminous efficacy (lm/W). Compare LED, CFL and incandescent brightness instantly with this free calculator.
  • Motor Full Load Current Calculator
    Calculate the full load amperes (FLA) of single- and three-phase electric motors from horsepower, voltage, efficiency, and power factor.
  • Three-Phase Current Calculator
    Calculate three-phase line current in amps from power, line voltage and power factor using I = P / (√3 × V × PF). Free and instant.
  • Capacitor Discharge Calculator (RC)
    Calculate the voltage across a discharging capacitor in an RC circuit using V(t)=V₀·e^(−t/RC). Find time constant, percent remaining and current.
  • RC / RL Time Constant Calculator (τ)
    Calculate the time constant τ for RC and RL circuits. RC: τ = R·C, RL: τ = L/R. Get τ in seconds, ms, µs and the 5τ settling time.

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