Practical energy decisions
Understand your home energy numbers
Estimate battery runtime, energy cost, portable power capacity, and small solar output with transparent formulas and adjustable assumptions.
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Battery Runtime Calculator
Estimate ideal, typical, and conservative battery runtime from voltage, amp-hours, load, discharge depth, and efficiency.
Battery Capacity Calculator
Estimate the amp-hour capacity needed for a target load and runtime.
Portable Power Station Runtime Calculator
Estimate portable power station runtime while accounting for usable capacity and converter losses.
Inverter Battery Runtime Calculator
Estimate how inverter efficiency and standby draw change battery runtime.
Appliance Electricity Cost Calculator
Estimate appliance energy use and electricity cost from watts, daily use, and your utility rate.
Watt-Hours to Amp-Hours Converter
Convert watt-hours to amp-hours at a specified nominal voltage.
Solar Panel Daily Output Calculator
Estimate daily solar production from array watts, peak sun hours, and system losses.
Solar Battery Size Calculator
Estimate solar battery amp-hours from daily energy, autonomy days, voltage, discharge depth, and efficiency.
Built for useful estimates
Every tool separates ideal arithmetic from typical and conservative planning estimates. Formulas, assumptions, uncertainty, examples, and sources appear alongside the calculator so you can judge the result.