Our Calculation Methodology

Calculations run in your browser. Each calculator exposes its formula and an example so you can reproduce the result with a spreadsheet or a handheld calculator.

Power and energy are different

Power in kilowatts (kW) is the rate of energy use or delivery. Energy in kilowatt-hours (kWh) is power multiplied by time. One kilowatt operating for two hours consumes two kilowatt-hours.

Prices and currencies

Default numbers are hypothetical examples. We do not fetch local tariffs, exchange rates, utility rules or equipment specifications. Changing currency updates the display label without converting the number you entered.

Efficiency

Charging efficiency is applied by dividing energy stored by the efficiency fraction to estimate input energy. Delivery efficiency is applied by multiplying stored energy by the efficiency fraction to estimate energy delivered to a load.

Model boundaries

Solar estimates use a simplified peak-sun-hours method, without a weather or location database. Battery tools estimate energy capacity and runtime, not inverter power or electrical design. Charging time uses average input power, not a complete charging curve.

Rounding and verification

Calculations retain full precision internally and display up to two decimal places. Small differences may appear when repeating calculations from rounded display values. Use the worked examples on each page to verify the inputs and arithmetic.