Electricity Calculator

  • Quarter Wave Antenna Length Calculator
    Calculate the ideal quarter-wave antenna length from frequency and velocity factor. Get results in meters, cm and inches instantly.
  • Kilowatts to Watts Calculator
    Convert kilowatts (kW) to watts (W) instantly. Enter a power value in kW and get the exact result in watts using W = kW × 1000.
  • Watts to Kilowatts Calculator
    Convert watts (W) to kilowatts (kW) instantly. Just divide power in watts by 1000 to get kilowatts. Fast, accurate, free W to kW converter.
  • Lumens Needed Calculator
    Calculate how many lumens you need to light a room. Multiply floor area (m²) by the recommended lux level to get total lumens for any space.
  • Electric Potential of a Point Charge Calculator
    Calculate the electric potential V of a point charge using V = kQ/r. Enter the charge in coulombs and distance in meters to get volts instantly.
  • Solar Panel Battery Charge Time Calculator
    Estimate how many hours of sunlight a solar panel needs to charge a battery from your battery Wh, panel watts, and system efficiency.
  • Thevenin Equivalent Calculator
    Compute the Thevenin equivalent of a circuit. Enter open-circuit voltage and short-circuit current to find Thevenin voltage Vth and resistance Rth.
  • Peak-to-Peak Voltage Calculator
    Convert between peak-to-peak (Vpp), peak (Vpeak) and RMS (Vrms) voltage for a sine wave. Enter any one value to get the others instantly.
  • Magnetic Field of a Long Straight Wire Calculator
    Calculate the magnetic field B around a long straight current-carrying wire using B = µ0·I/(2π·r). Enter current and distance to get tesla, µT and gauss.
  • Resistance Temperature Coefficient Calculator
    Calculate how a conductor resistance changes with temperature using R = R₀(1 + α·ΔT). Enter reference resistance, temperature coefficient and temperatures.
  • Electric Potential Energy Calculator
    Calculate the electric potential energy between two point charges using U = kQ1Q2/r. Enter charges in coulombs and distance in meters to get joules.
  • Battery C-Rate Calculator
    Calculate charge/discharge current from battery capacity and C-rate using I = C-rate × Capacity. Get amps plus the theoretical full charge/discharge time.
  • Synchronous Speed Calculator
    Calculate the synchronous speed of an AC motor or generator from supply frequency and number of poles using Ns = 120f/P. Get results in RPM and rev/s.
  • VinFast Charge Time from Amps Calculator
    Estimate VinFast EV charging time from charger power (kW), battery capacity, and start/target charge percent. Quick, simple hours and minutes estimate.
  • LED Wire Voltage Drop Calculator
    Calculate the voltage drop in wires feeding an LED or LED strip. Enter current, length, wire area and material to find loss, voltage at the LED and power waste.
  • Cost Per kWh Calculator
    Find your effective electricity rate per kWh by dividing your total monthly bill by the kilowatt-hours used. Fast, free energy cost calculator.
  • Voltage Drop Percentage Calculator
    Calculate voltage drop percentage (VD%) from source voltage and voltage drop. Check if your circuit meets the common 3% / 5% limits instantly.
  • Watts to kWh Calculator
    Convert watts and run time to kilowatt-hours (kWh). Enter device power and hours used to find energy consumption for billing or efficiency checks.
  • Residential Electrical Load Calculator (NEC)
    Estimate a US home's total electrical load (VA) and service size in amps using NEC general-lighting, small-appliance, and fixed-appliance loads.
  • Annual Appliance Running Cost Calculator
    Calculate the yearly electricity cost of any appliance from its wattage, daily usage hours, and your price per kWh. Get annual, monthly, and daily costs.
  • VinFast VF7 Charging Cost Calculator
    Estimate the electricity cost to charge your VinFast VF7. Enter battery size, start and target charge, charging efficiency, and your power price.
  • VinFast VF8 Charging Cost Calculator
    Estimate the cost to charge your VinFast VF8 EV from any start to target charge level, factoring in electricity price and charging efficiency.
  • VinFast VF9 Charging Time Calculator
    Estimate how long it takes to charge a VinFast VF9 EV from any start to target percent using your charger power, battery size, and efficiency.
  • VinFast VF6 Charging Cost Calculator
    Estimate the cost to charge your VinFast VF6 EV. Enter battery size, electricity price, start and target charge, and efficiency to get the dollar cost.

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