20 Ω resistor colour code (20R)
E24 series
20 Ω reads as Red · Black · Black in bands. With ±5% it may sit anywhere from 19 Ω to 21 Ω.
Five bands
The first two bands are digits; the third is how many zeros follow. The gold band at the end is the ±5% tolerance.
- Value
- 20 Ω
- 4k7 notation
- 20R
- Four bands
- Red · Black · Black · Gold
- Five bands
- Red · Black · Black · Gold · Gold
- Multiplier
- ×10⁰
- Tolerance
- ±5%
- Actual range
- 19 – 21 Ω
- Series
- E24 series
Which end to start from · The tolerance band sits a little apart from the rest. Start from the crowded end. If you can see gold or silver, that band is the last one.
Same decade
The same twenty-four values repeat with a different number of zeros — 47 Ω, 470 Ω and 4.7 kΩ all start with the same two colours.
Nearby values
How to read this
- Colours are digits: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9.
- The third band counts the zeros. Yellow, violet, red means 47 with two zeros — 4.7 kΩ.
- A five-band resistor reads three digits, so its multiplier band drops by one step.
- The tolerance band sits slightly apart, which is how you know which end is the back.
Frequently asked questions
Q. What are the colour bands for 20 Ω?
Red · Black · Black · Gold in four bands, or Red · Black · Black · Gold · Gold in five.
Q. How is 20 Ω read?
The first two digits are 20, followed by 0 zeros, giving 20 Ω. In short form, 20R.
Q. What is the real value once tolerance is counted?
At ±5% it lies between 19 Ω and 21 Ω.
Q. Is 20 Ω a common value?
It belongs to E24. You will find it wherever the full E24 range is stocked.