Electronics calculators
Work out circuit values before choosing components. These calculators cover resistor color codes, Ohm's law, voltage dividers, parallel resistance, LED resistors and battery runtime. Use the decoders and conversion tables to read capacitor markings or compare wire sizes. Each tool shows its units, formulas and assumptions alongside the result.
Resistor color code calculator
Read a 4, 5 or 6 band resistor's value from its colors, or enter a resistance to find the matching bands.
Ohm's law calculator
Enter two circuit values to calculate voltage, current, resistance and power, with units and formulas.
LED series resistor calculator
Calculate an LED series resistor and its power dissipation from the supply voltage, forward voltage and current.
Voltage divider calculator
Find the output voltage of a two-resistor divider, or solve for either resistor value.
Parallel resistor calculator
Calculate total resistance for resistors in parallel or series. Add values and compare how current divides.
Ceramic capacitor decoder
Decode three-digit capacitor markings and show the capacitance in picofarads, nanofarads and microfarads.
AWG wire gauge converter
Convert American Wire Gauge sizes to wire diameter and cross-sectional area in metric or imperial units.
Battery life calculator
Estimate battery runtime from capacity and current draw. Adjust usable capacity to compare scenarios.
