LED Resistor Calculator LED Resistor Calculator

LED series resistor calculator

The calculator applies Ohm law to find a resistor that limits LED current for a selected supply voltage.

Leave safety margin for resistor wattage and check LED datasheets before building a circuit.

Use the calculator to turn input values into a clear, repeatable result.
Keep units and assumptions visible so the calculation can be checked later.
Copy the result or key numbers for reports, messages or spreadsheets.
Reset to defaults when you want to compare another scenario from a clean state.
Calculators run in the browser and are useful for quick estimates before formal checks.
For finance, health, engineering or legal decisions, verify important results with a specialist or official source.