Home Electricity Usage and Time-of-Use Solar Calculators

Home Electricity Usage Calculator

Tip: on a phone, swipe the table sideways.

Add each appliance's power (watts, on its label or manual), hours used per day and days used per month. Leave rows you do not need at 0.

Time-of-Use and Export Credit Solar Estimator

Solar is worth most when you use the electricity yourself while you would otherwise pay a high rate. Enter your own numbers to compare scenarios.

Methodology and limitations

• Usage: kWh per month = watts x hours per day x days per month / 1,000. Cost = kWh x the rate you enter. Real appliances cycle (fridges, heat pumps) so label wattage can overstate use; a plug-in energy monitor or your smart-meter data is more accurate.
• Solar value: production = system kW x yearly kWh per kW. Self-use value = production x self-use share x your solar-hours rate. Export value = the remaining production x your export credit. Total = the two added together. It ignores fixed or minimum charges, panel degradation, shading, rate changes, taxes and the cost of the system, so it is not a payback or savings figure.
• Defaults are placeholders to show how the tool works, not your local rates. Use the numbers on your own bill and your utility's tariff sheet.

Related: how to read your electric bill, payback calculator, is solar plus battery worth it?