Step-by-step instructions
- Enter or select Supply voltage (V).
- Enter or select LED forward voltage (V).
- Enter or select LED current (A).
- Tap Calculate.
- Review the result shown directly below the calculator.
LED Series Resistor Calculator
Calculate LED resistor R = (Vs−Vf)/I.
How to use the LED Series Resistor Calculator
Calculate LED resistor R = (Vs−Vf)/I.
What the inputs mean
- Supply voltage (V)
- Enter the value requested by this field label.
- LED forward voltage (V)
- Enter the value requested by this field label.
- LED current (A)
- Enter the value requested by this field label.
Formula or calculation method
The calculator applies the standard mathematical relationship for the labeled inputs and returns the computed result automatically.
Example
Try entering realistic values for Supply voltage (V) and LED forward voltage (V), then tap Calculate to see how the result changes.
How to understand the result
Use the result as an estimate based on the values you entered. For planning decisions, double-check that the input units and assumptions match your real situation.
Tip: Keep all values in compatible units and use values from the same time period when the calculator compares two amounts.