CURRENT LIMITING RESISTOR CALCULATOR

FOR LIGHT EMITTING DIODES

The calculators on this page can be used to find current limiting resistors and currents for Light Emitting Diodes.

The first calculator determines the resistance for a desired LED current while the second calculates the current for a given resistance.

LED - CURRENT LIMITING RESISTOR CALCULATOR

Supply Voltage

VOLTS

Voltage Drop Across LED

VOLTS

Desired LED Current

MILLIAMPS

Calculated Limiting Resistor

OHMS

Calculated Resistor Wattage

WATTS

LED - CURRENT CALCULATOR

Supply Voltage

VOLTS

Voltage Drop Across LED

VOLTS

Resistor Value

OHMS

Calculated LED Current

MILLIAMPS

Calculated Resistor Wattage

WATTS

Voltages in Volts - Current in Milliamps - Resistance in Ohms

When selecting resistors - It is advisable to choose the next higher standard value.

A browser capable of running Javascript is required for this calculator.

If LED's are connected in series - ADD their voltage drops together to get the total voltage drop.

If LED's are connected in parallel - ADD their current ratings together to get the total Desired Led Current

Entering a zero for the LED voltage drop will yield the resistance and wattage for a resistance only circuit.