LED resistor calculator with standard values

  1. Input
  2. Result

The next standard value is rounded upward, allowing for the resistor’s minimum tolerance value. Power rating uses at least twice the calculated worst-case dissipation.

A simplified DC model with fixed LED forward voltage. Verify the LED datasheet, supply variation, temperature and derating. Each parallel string needs its own resistor; this is not a high-power LED driver design.

Quick start

Select an upward standard resistor value for one LED string.

  1. Enter supply, forward voltage, current and LED count
  2. Choose E12 or E24 and resistor tolerance
  3. Calculate and check current and power before building

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