100 kΩ resistor colour code
brownblackyellowgold
100 kΩ ±5%
brown black yellow gold — four bands, read from the end with the bands closest to it.
| Band 1 — first digit | brown = 1 |
| Band 2 — second digit | black = 0 |
| Band 3 — multiplier | yellow × 10,000 |
| Band 4 — tolerance | gold ± 5% |
| Value | 100 kΩ |
| Acceptable range | 95 kΩ to 105 kΩ |
Reading it
The two digit bands give 10 and the multiplier band multiplies it by 10,000:
10 × 10,000 = 100 kΩ
Which end to start from is the part that catches people. The tolerance band is the one set slightly apart from the other three, and it is gold or silver far more often than not — neither of which is a digit colour, so a gold or silver band tells you which end you are at. Read from the opposite end.
What ±5% actually means
A 100 kΩ ±5% resistor is in specification anywhere from 95 kΩ to 105 kΩ. A meter reading of 95 kΩ on this part is not a fault and not a reason to replace it.
100 kΩ is one of the E24 values — the 24 steps per decade that ±5% resistors are made in. The steps are spaced so that the tolerance bands of neighbouring values just about touch: there is no gap between one value's range and the next, and no point making anything in between. It is the same reasoning that gives ±10% parts only 12 values per decade.
The same resistor with five bands
Precision resistors carry five bands: three digits, a multiplier and a tighter tolerance. The same 100 kΩ reads
brownblackblackorangebrown
— brown black black orange brown. The digits become 1, 0 and 0, and the multiplier drops one decade to orange to compensate. The brown final band is ±1% rather than ±5%, which narrows the range to 99 kΩ–101 kΩ.
How much this one can take
A resistor's limit is heat, not voltage or current on their own: the power it turns into heat is V² ÷ R, so the same wattage allows very different numbers at 100 kΩ than it does at a value ten times away. This is the part of a colour code lookup people actually came for and charts leave out.
| Rating | Maximum current | Maximum voltage |
|---|---|---|
| ⅛ W | 1.1 mA | 111.8 V |
| ¼ W | 1.6 mA | 158.1 V |
| ½ W | 2.2 mA | 223.6 V |
| 1 W | 3.2 mA | 316.2 V |
The quarter-watt part is the one in everybody's drawer: at 100 kΩ it will carry 1.6 mA or stand 158.1 V across it, and not both at once — those are the same limit expressed two ways.
100 kΩ is a ±10% value too
100 kΩ is one of the twelve E12 values as well as one of the twenty-four E24 ones, which means it is made at ±10% and ±5% both. In practice that makes it easier to find and cheaper: E12 values are what a beginner's assortment box contains, and a shop that stocks one range stocks this value.
The nearest E12 value is 100 kΩ — this one.
The same resistor as a surface-mount marking
Surface-mount resistors have no room for bands, so they carry printed digits instead — and 104 is what 100 kΩ looks like on one. The scheme is the colour code with the colours replaced by the digits they stood for: two significant figures and a count of zeros.
| Marking | Used on | Reads as |
|---|---|---|
104 | Three-digit, ±5% parts | 10 followed by 4 zeros |
1003 | Four-digit, ±1% parts | 100 followed by 3 zeros |
A four-digit marking is not a different system, only a more precise one: it carries three significant figures instead of two and takes one off the zero count, which is why 104 and 1003 are the same 100 kΩ. If a board has both on it, the four-digit parts are the ±1% ones.
Very small ±1% parts use a third scheme, EIA-96, where two digits index a table of values and a letter gives the multiplier — 01C rather than 1002. It only covers the E96 series, so it has no marking for most of the E24 values on this site, and a marking with a letter in the middle is never one of these codes.
Where 100 kΩ turns up
Hundreds of kilohms is high-impedance territory: op-amp bias, timing networks with small capacitors, and the top half of a voltage divider reading a high voltage. At these values board leakage and finger grease start to matter, and a dirty board can measurably shift a circuit.
Frequently asked questions
What is the colour code for a 100 kΩ resistor?
brown black yellow gold on a four-band resistor: brown for 1, black for 0, yellow for a multiplier of ×10,000, and gold for ±5%.
What resistor is brown black yellow gold?
100 kΩ, ±5%. The first two bands are the digits 1 and 0, the third multiplies by 10,000, and the gold band is the tolerance.
What is the tolerance range of a 100 kΩ ±5% resistor?
95 kΩ to 105 kΩ. A resistor measuring anywhere in that range is within specification, which is why a meter reading of 95 kΩ on a 100 kΩ part is not a fault.
What is the five-band code for 100 kΩ?
brown black black orange brown — three digit bands (1, 0, 0), then orange as the multiplier and brown for ±1%. Five-band resistors carry an extra significant figure, so the third digit is the zero that a four-band code leaves to the multiplier.
Nearby values
- 110 kΩ resistor colour code — brown brown yellow gold
- 120 kΩ resistor colour code — brown red yellow gold
- 130 kΩ resistor colour code — brown orange yellow gold
- 150 kΩ resistor colour code — brown green yellow gold
- 160 kΩ resistor colour code — brown blue yellow gold
- 180 kΩ resistor colour code — brown grey yellow gold
- 200 kΩ resistor colour code — red black yellow gold
- 220 kΩ resistor colour code — red red yellow gold
- 240 kΩ resistor colour code — red yellow yellow gold
- 270 kΩ resistor colour code — red violet yellow gold