Electrical & Engineering Calculators

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Electrical & Engineering Calculators

7 free calculators for electronics, circuit design, and engineering problems.

Ohm's Law Calculator Resistor Color Code Capacitor Charge Calculator Voltage Divider Calculator LED Resistor Calculator Decibel (dB) Converter Torque Calculator

Electronics and Engineering Calculators

Designed for students, hobbyists, and engineers, these 7 tools cover the most common calculations in electronics and mechanical engineering. Whether you are wiring an LED, designing a voltage divider, or calculating the torque on a bolt, these calculators give you instant results.

Electronics Tools

Ohm's Law Calculator solves for voltage, current, or resistance given the other two values — the most fundamental calculation in circuit design. Resistor Color Code decodes the coloured bands on through-hole resistors and displays the resistance and tolerance. Capacitor Charge Calculator computes charge (Q), voltage (V), or capacitance (C) using Q = CV. Voltage Divider Calculator calculates the output voltage of a resistive divider network. LED Resistor Calculator tells you the exact series resistor value needed for any LED given your supply voltage and LED specifications.

Signal and Mechanical Tools

The Decibel (dB) Converter converts between power ratios, voltage ratios, and decibels for audio, RF, and optics applications. The Torque Calculator computes torque, force, or lever arm length, with support for both metric (Nm) and imperial (lb-ft) units.

What is Ohm's Law?
Ohm's Law states that V = I × R, where V is voltage in volts, I is current in amperes, and R is resistance in ohms. Given any two values, the calculator solves for the third.
How do I read a resistor color code?
Select the colours of each band in the Resistor Color Code tool — it supports 4-band and 5-band resistors. The tool displays the resistance in ohms plus the tolerance percentage.