20 Ω resistor colour code
Four bands: Red · Black · Black · Gold. The first two give the digits, the third multiplies, the fourth states how far off the real part may be.
Nominal
20 Ω
20 ohms
Real range at ±5%
19 Ω – 21 Ω
A gold band allows this much drift.
Series
E24
E24 only — stocked less often.
Band by band
| Band | Colour | Meaning |
|---|---|---|
| 1 | Red | 1st digit — 2 |
| 2 | Black | 2nd digit — 0 |
| 3 | Black | Multiplier — ×1 |
| 4 | Gold | Tolerance — ±5% |
How much it can take
Current and dissipation across the resistor, and the package you need. The suggested rating keeps a factor of two in hand, which is what anyone building a board actually does.
| Across it | Current | Dissipated | Package to pick |
|---|---|---|---|
| 3.3 V | 165 mA | 545 mW | 2 W |
| 5 V | 250 mA | 1.25 W | 5 W |
| 12 V | 600 mA | 7.2 W | no standard part — needs a power resistor or a heatsink |
| 24 V | 1.2 A | 28.8 W | no standard part — needs a power resistor or a heatsink |
What you can actually get
Parts made
215
21st most of 1,465 values
In stock
31,339
across 11 of them
Cheapest at 100
$0.001
each
Tolerances sold
±0.05% to ±5%
8 grades in all
Packages: 0805, 0603, 1206, 0402, 1210, 2512, 2010, 0207. Ratings: 30mW to 100W.
Assembly stock from the JLCPCB library, read 2026-09-24. That is what a board house will place for you — not everything a distributor sells.
The same value, marked differently
Five bands
RedBlackBlackGoldBrown
Three significant digits and a ±1% band.
Values that can overlap this one
At ±5% the tolerance bands of neighbouring values run into each other. A part sold as one of these could measure the same as a 20 Ω — which is why measuring beats reading when it matters.
- 19.1 Ω18.909 Ω–19.291 Ω
- 19.6 Ω19.404 Ω–19.796 Ω
- 20.5 Ω20.295 Ω–20.705 Ω
- 21 Ω20.79 Ω–21.21 Ω
- 22 Ω20.9 Ω–23.1 Ω
If you do not have one
Standard values that land within 1% of 20 Ω when combined.