⚡ CircuitCalc
20 free electronics calculators for engineers, students & hobbyists. All calculations run in your browser — no data sent anywhere.
Ohm's Law
Calculate voltage, current, resistance and power
Resistor Color Code
Decode 4/5/6 band resistor color codes
LED Resistor
Find the right resistor for your LED circuit
Voltage Divider
Calculate output voltage from a resistor divider
Capacitor Code
Decode ceramic capacitor 3-digit codes
555 Timer
Astable & monostable 555 timer circuits
RC Time Constant
Calculate RC circuit charge/discharge timing
Parallel Resistance
Calculate equivalent resistance of parallel resistors
Power Calculator
Calculate electrical power from V, I, R
Frequency ↔ Wavelength
Convert between frequency and wavelength
PCB Trace Width
IPC-2221 trace width calculator for current capacity
SMD Resistor Code
Decode 3/4 digit SMD resistor codes
Wire Gauge (AWG)
AWG wire reference table with current ratings
Battery Life
Estimate battery runtime from capacity and load
dB Converter
Convert between dB, power, and voltage ratios
Inductor Color Code
Decode inductor color band values
Reactance (XL/XC)
Calculate inductive and capacitive reactance
Op-Amp Gain
Inverting & non-inverting op-amp gain calculator
Filter Cutoff Frequency
Calculate RC/RL filter cutoff frequency
Star-Delta Transform
Convert between star (Y) and delta (Δ) networks