LED Resistor Calculator
Pick the right current-limiting resistor for an LED and see the nearest standard value.
R = (supply voltage − LED forward voltage) ÷ LED current. The result is rounded up to the next E24 standard value, and power = I² × R.
Results are estimates for planning and learning. Check important numbers against your own data and a qualified professional. Everything is calculated in your browser; nothing you enter is sent anywhere.