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Electrical Engineering Tools

Fast, free calculators and references for everyday electronics — Ohm’s law, resistor codes, filters, timers and more. Everything runs in your browser.

13 tools

Ohm’s Law Calculator
Enter any two of voltage, current, resistance or power — the other two are solved instantly.
Calculator
Voltage Divider Calculator
Solve a resistive divider for any unknown, handle a loaded output, and pick standard-value resistor pairs.
Calculator
LED Series Resistor Calculator
Size the series resistor for one or more LEDs, with a safe standard value, real current and power.
Calculator
555 Timer Calculator
Compute astable frequency and duty or monostable pulse width, and reverse-design resistors for a target.
Calculator
PWM Duty Cycle Calculator
Convert between frequency, duty cycle, on/off times and average voltage, with a bit-depth resolution helper.
Calculator
Battery Life Estimator
Estimate how long a battery lasts from its capacity, average load current and a real-world derating factor.
Calculator
Resistor Color Code Calculator
Decode 4-, 5-, and 6-band resistors to a value, tolerance and tempco — or turn a value into its colour bands.
Decoder
Capacitor Code Decoder
Decode a 3-digit ceramic capacitor code and tolerance letter to a value — or encode a capacitance back to its code.
Decoder
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Wire Gauge & Ampacity Reference
Look up AWG wire properties and ampacity, size a gauge for a target current, and estimate voltage drop over a run.
Reference
RC / RL Filter Calculator
Compute time constant, cutoff frequency and step response for a first-order RC or RL filter, with preferred-value design.
Calculator
Engineering Unit Converter
Convert voltage, current, power, energy, frequency, charge and more between units — including logarithmic dBm, dBW and dBV.
Converter
PCB Trace Width Calculator
Size a PCB trace for a target current and temperature rise with IPC-2221, then read its resistance, voltage drop and power loss.
Calculator
Logic Gate Simulator
Type a boolean expression and get its full truth table and canonical sum-of-products — AND, OR, NOT, XOR, NAND, NOR, XNOR.
Simulator