Engineering Tools & Calculators

Free online calculators and engineering resources for your projects

Ohm's Law Calculator

Resistor Color Code

LED Resistor Calculator

Voltage Divider

Ohm's Law Calculator

Enter any 2 of the 3 values (V, I, R) to calculate the third.

Voltage (V)

Current (I)

Resistance (R)

Select color bands to decode resistor value.

Band 1

Band 2

Band 3

Multiplier

= 471.0 kΩ

Calculate the series resistor needed for an LED circuit.

Supply Voltage (V)

LED Forward Voltage (V)

LED Current (mA)

Calculate output voltage for a resistive voltage divider.

Input Voltage (V)

R1 (kΩ)

R2 (kΩ)