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The Toolbox — Calculators

Electrical, Wiring & Bench

Ohm's Law, voltage divider, resistor color code, wire gauge, power factor, time constant, resonant frequency, and capacitor calculators.

Ohm's Law Calculator

Enter any two values to calculate the third. V = I × R

Voltage Divider Calculator

Calculate output voltage from two resistors, or find R2 needed for a target voltage.

Vout = Vin × R2 / (R1 + R2)

Resistor Color Code Decoder

Select band colors to calculate resistance value and tolerance.

Color Reference

Black = 0
Brown = 1
Red = 2
Orange = 3
Yellow = 4
Green = 5
Blue = 6
Violet = 7
Gray = 8
White = 9

Wire Gauge Calculator

Look up AWG wire specifications or find the correct gauge for a given current and run length.

Diameter1.63 mm
Cross-section2.08 mm²
Ampacity — Chassis wiring15 A
Ampacity — Power transmission13 A
Ampacity — Bundled/conduit10 A
Resistance0.00414 Ω/m

Power Factor Calculator

Calculate true power, apparent power, reactive power, and power factor for AC circuits.

True Power (W) = Apparent Power (VA) × Power Factor

Time Constant Calculator

Calculate RC or RL time constants and charging/discharging milestones.

Resonant Frequency Calculator

Calculate LC resonant frequency, or find L or C needed to resonate at a target frequency.

Capacitor Charge / Discharge Calculator

Calculate capacitor voltage at any point during charging or discharging.