100 Ω resistor colour code (100R)
E6 series
100 Ω reads as Brown · Black · Brown in bands. With ±5% it may sit anywhere from 95 Ω to 105 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
- 100 Ω
- 4k7 notation
- 100R
- Four bands
- Brown · Black · Brown · Gold
- Five bands
- Brown · Black · Black · Black · Gold
- Multiplier
- ×10¹
- Tolerance
- ±5%
- Actual range
- 95 – 105 Ω
- Series
- E6 series · E12 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 100 Ω?
Brown · Black · Brown · Gold in four bands, or Brown · Black · Black · Black · Gold in five.
Q. How is 100 Ω read?
The first two digits are 10, followed by 1 zeros, giving 100 Ω. In short form, 100R.
Q. What is the real value once tolerance is counted?
At ±5% it lies between 95 Ω and 105 Ω.
Q. Is 100 Ω a common value?
It belongs to E6. That is the coarsest series, so it turns up everywhere.