LED series resistor
calculator.

Find a standard resistor for a low-voltage DC LED string, then check current and power at the edges of your part tolerances.

Set up the circuit

DC supply

Nominal supply (V) Supply tolerance (±%)

LEDs in series

Number of LEDs Current limit (mA)

Minimum V_F (V) Typical V_F (V) Maximum V_F (V)

Use the forward voltage range from the LED’s datasheet at the intended current.

Resistor tolerance

Resistor tolerance (±%)

E24 series