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.