How do I read the resistor color code?

This calculator generates a standard 4-band code. The first two bands represent the significant digits, the third band is the multiplier (number of zeros), and the fourth (Gold) represents 5% tolerance.

LED Series Resistor Calculator & Color Code Visualizer

LED Resistor Calculator | Visual Color Code & Wattage

Calculates the precise current limiting resistor value for your LED circuits. This tool uses Ohm’s Law to ensure your Light Emitting Diodes operate safely without burning out.

Circuit Details

Input

Source Voltage (Vs)

LED Color

Forward Voltage (Vf)

LED Current (If)

LEDs in Series

Pcs

Component Selection

Output

Part Preview

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Calculated Resistance

Use Standard (E24)

Rec. Wattage

Size

Design Note

Values calculated for safety (2x power factor).

Typical Forward Voltages (Vf)

Color	Voltage (V)
Red	1.8 – 2.1
Amber	2.0 – 2.2
Green	2.0 – 3.1
Blue	3.0 – 3.7
White	3.0 – 3.4

FAQ & Troubleshooting

Why did my LED burn out?

Usually because the resistor value was too low, allowing too much current. Use the “Rec. Wattage” shown above to ensure your resistor handles the heat.

Does resistor orientation matter?

No. Resistors are not polarized. You can install them in either direction on the positive (anode) or negative (cathode) side.