Resistor Calculators
6 tools
Free online resistor calculators for electronics design. Calculate resistance using Ohm's Law, design voltage dividers, find LED current limiting resistors, and determine pull-up resistor values.
Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law. Enter any two values to find the rest instantly.
LED Resistor Calculator
Calculate the correct current-limiting resistor value for your LED circuit. Get power dissipation and nearest standard resistor values.
Voltage Divider Calculator
Design voltage dividers with ease. Calculate resistor values or output voltage for your circuit.
Pull-up Resistor Calculator
Calculate general-purpose pull-up and pull-down resistor values. Consider input thresholds and load current.
I2C Pull-up Resistor Calculator
Calculate optimal I2C pull-up resistor values based on bus capacitance and speed mode. Supports Standard, Fast, and Fast Mode Plus.
Resistor Color Code Calculator
Decode resistor color bands to find the value, or find color bands for a given resistance. Supports 4, 5, and 6 band resistors.