LED resistor on 5 V by color (20 mA, E12 values)
| LED | Vf (typ.) | Exact R | E12 resistor | Current | Resistor power |
|---|---|---|---|---|---|
| Red | 2.0 V | 150 Ω | 150 Ω | 20.0 mA | 60 mW |
| Orange | 2.0 V | 150 Ω | 150 Ω | 20.0 mA | 60 mW |
| Yellow | 2.1 V | 145 Ω | 150 Ω | 19.3 mA | 56.1 mW |
| Green (standard) | 2.2 V | 140 Ω | 150 Ω | 18.7 mA | 52.3 mW |
| Green (bright/true green) | 3.2 V | 90 Ω | 100 Ω | 18.0 mA | 32.4 mW |
| Blue | 3.2 V | 90 Ω | 100 Ω | 18.0 mA | 32.4 mW |
| White | 3.2 V | 90 Ω | 100 Ω | 18.0 mA | 32.4 mW |
Typical forward voltages; check your LED's datasheet. Rounding up to the next standard value keeps the current at or just below 20 mA.
Frequently asked questions
What resistor for a white or blue LED on 5 V?
About 90 Ω exact at 20 mA (Vf ≈ 3.2 V), so use 100 Ω.
How many red LEDs can I put in series on 5 V?
As a rule of thumb keep at least 1 V across the resistor: 2 red LEDs in series (4.0 V in total) with 56 Ω at 20 mA.
Can I use a bigger resistor?
Yes. A larger value just lowers the current and brightness; most modern LEDs are clearly visible at 5–10 mA.