LED Current-Limiting Resistor Calculator

Engineering Tool · Hongcheng Optoelectronics (Member of Guangyu Group)

Enter supply voltage, LED forward voltage and target current to get the required resistor value (with E24 standard recommendation) and power derating advice. For small SMD indicator LEDs (0201–1206), 5–10 mA typically provides sufficient brightness.

Formula: R = (Vs − Vf × n) / If. Forward voltage varies by color (red/yellow ≈ 1.8–2.2V, blue/green/white ≈ 2.8–3.4V) — calculate separately per color when mixing. For exact part parameters, see our Datasheet Center or contact sales: +86-139-2571-4318.