These 23 tools are grouped into three areas: solar & off-grid power for sizing panels, batteries, and inverters; home wiring & panel for load, wire size, conduit, and breaker calculations; and circuits & electronics for resistors, capacitors, and other component-level math. Every tool runs entirely in your browser.
Solar & Off-Grid6 tools
Size solar arrays, battery banks, inverters, and charge controllers for off-grid or backup power systems, and estimate payback time.
Size a solar panel array based on your daily energy usage.
Off-Grid Solar System CalculatorPlan a complete off-grid solar setup: panels, batteries, and inverter.
Solar Battery Bank CalculatorCalculate the battery bank capacity needed for your solar backup power.
Solar Inverter Sizing CalculatorChoose the right inverter size for your solar or backup power system.
Solar Payback CalculatorEstimate how long it takes for solar panels to pay for themselves.
Solar Charge Controller CalculatorFind the right charge controller size and type for your solar array.
Home Wiring & Panel7 tools
Calculate electrical loads, wire sizes, voltage drop, conduit fill, breaker sizing, and three-phase power for residential and light commercial wiring.
Calculate your home's total electrical load per NEC 220.82.
Wire Size & Voltage Drop CalculatorFind the correct wire gauge and check voltage drop for a circuit.
Conduit Fill CalculatorDetermine the right conduit size for your wire count and gauge.
Electricity Cost CalculatorEstimate the running cost of any appliance based on wattage and usage.
Breaker Size CalculatorFind the correct circuit breaker size for your load and wire gauge.
Three-Phase Power CalculatorCalculate power, current, and voltage for three-phase electrical systems.
Ohm's Law CalculatorSolve for voltage, current, resistance, or power using Ohm's Law.
Circuits & Electronics10 tools
Resistor, capacitor, and timing calculators for electronics hobbyists and PCB design. Working from a datasheet curve? The Interpolation & Extrapolation Calculator in Math & Science can help.
Decode resistor color bands to find resistance and tolerance.
Series & Parallel Resistor CalculatorCalculate total resistance for resistors in series or parallel.
LED Resistor CalculatorFind the right resistor value to safely power an LED.
Voltage Divider CalculatorCalculate output voltage for a two-resistor voltage divider circuit.
Capacitor Code & Charge/Discharge CalculatorDecode capacitor codes and calculate charge and discharge time.
RC Time Constant CalculatorCalculate the time constant for a resistor-capacitor circuit.
Battery Life & Capacity CalculatorEstimate battery runtime based on capacity and load current.
Decibel (dB) CalculatorConvert between power ratios, voltage ratios, and decibels.
555 Timer CalculatorCalculate timing, frequency, and duty cycle for a 555 timer circuit.
PCB Trace Width CalculatorCalculate minimum PCB trace width for a given current and copper weight.
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