Electricity Cost Calculator
What does a device cost to run? Watts, hours and your price give the kWh and the cost per day, month and year.
Free tools
Free Utility & Electricity Calculators
Simple calculators for your electricity costs and electrical power. Free, no sign-up, and they run in your browser.
Electricity costs
What your appliances and your bill really cost.
Electricity Bill Calculator
Estimate your electricity bill from the kWh used, your price per kWh, a fixed fee and tax.
Appliance Energy Usage Calculator
How much electricity does a fridge, heater, AC or TV use? kWh and cost per day and year.
Electrical power
Convert between watts, amps, volts, kW, kWh and kVA.
Watts to Amps Calculator
Convert watts to amps or amps to watts for DC, single-phase and three-phase circuits.
kW to kWh Calculator
Convert kilowatts to kilowatt-hours with the hours of use, or kWh back to kW.
Ohm's Law Calculator
Fill in any two of volts, amps, ohms and watts and get the other two.
kVA to kW Calculator
Convert kVA to kW or kW to kVA using the power factor.
Battery Runtime Calculator
How long will a battery run a device? Capacity, voltage, load, usable share and inverter losses.
Energy Unit Converter
Convert kWh, Wh, MWh, MJ, GJ, BTU, therm and kcal into each other.
Amps to Watts Calculator
Convert amps to watts and kW, from the current and the voltage. DC, single-phase or three-phase.
kVA to Amps Calculator
Convert kVA to amps, or amps to kVA, for single-phase and three-phase supplies, generators and transformers.
Gas, heating oil & EV charging
Turn gas or oil into kWh, and see what a charge costs.
EV Charging Cost Calculator
What does a charge cost, and how far does it take you? Battery, charge level, price and losses.
Gas m³ to kWh Calculator
Convert gas volume in m³ to kWh with your calorific value, and see the cost.
Heating Oil Litres to kWh Calculator
Convert litres of heating oil (Heizöl) to kWh and back, and see the cost per kWh.
EV Charging Time Calculator
How long does a charge take? Battery, charge levels and the wallbox or charger power.
Water, meters & shared bills
Water use and cost, meter readings, and how to share a utility bill fairly.
Water Bill Calculator
Estimate your water bill from the m³ used, the water and wastewater price, a fixed fee and tax.
Utility Bill Split Calculator
Split a utility bill evenly, or by each person's or flat's consumption.
Meter Reading Calculator
Two meter readings give your consumption per day, month and year, and the cost. Electricity, gas or water.
Water Usage Calculator
How much water does your household use? Showers, toilets and laundry give litres or gallons per day, and the cost.
Solar, heat pumps & air conditioning
Estimate solar yield and payback, size a heat pump (Wärmepumpe) or an air conditioner, and see the running cost.
Solar Panel Output Calculator
How many kWh do your solar panels make? Convert kWp to kWh per day, month and year.
Solar Payback Calculator
How many years until your solar system has paid for itself? Cost, production, own use and tariffs.
Heat Pump Running Cost Calculator
Wärmepumpe or gas boiler? Yearly electricity use and cost of a heat pump against your current heating.
Heat Pump Size Calculator
A first estimate of the heating load (kW) your Wärmepumpe has to cover, from living area and building type.
Heating Oil to Heat Pump Calculator
How much electricity would a Wärmepumpe need to replace your heating oil, and what does it cost?
BTU & AC Size Calculator
What size air conditioner does a room need? BTU per hour, kW and tons from the room size.
About these calculators
Every calculator shows its formula and the example it starts with, so you can check the result yourself. The numbers you enter stay in your browser; nothing is sent or stored.
They give estimates for planning. Your supplier's bill, or the label on a device, is always the final word.
Tired of typing in meter readings?
UtilityControl tracks your meters, readings and costs for you, on your phone and on the web, and it starts free.