300 kΩ resistor colour code
orangeblackyellowgold
300 kΩ ±5%
orange black yellow gold — four bands, read from the end with the bands closest to it.
| Band 1 — first digit | orange = 3 |
| Band 2 — second digit | black = 0 |
| Band 3 — multiplier | yellow × 10,000 |
| Band 4 — tolerance | gold ± 5% |
| Value | 300 kΩ |
| Acceptable range | 285 kΩ to 315 kΩ |
Reading it
The two digit bands give 30 and the multiplier band multiplies it by 10,000:
30 × 10,000 = 300 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 300 kΩ ±5% resistor is in specification anywhere from 285 kΩ to 315 kΩ. A meter reading of 285 kΩ on this part is not a fault and not a reason to replace it.
300 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 300 kΩ reads
orangeblackblackorangebrown
— orange black black orange brown. The digits become 3, 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 297 kΩ–303 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 300 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 | 645 µA | 193.6 V |
| ¼ W | 913 µA | 273.9 V |
| ½ W | 1.3 mA | 387.3 V |
| 1 W | 1.8 mA | 547.7 V |
The quarter-watt part is the one in everybody's drawer: at 300 kΩ it will carry 913 µA or stand 273.9 V across it, and not both at once — those are the same limit expressed two ways.
300 kΩ exists only at ±5%
300 kΩ is an E24 value that is not in the E12 series, so it is made at ±5% and tighter but not at ±10%. That is why it is missing from cheap assortment boxes, which are usually E12 only — and why a design that calls for 300 kΩ is harder to service from a beginner's drawer than one that calls for 270 kΩ.
The nearest E12 value is 270 kΩ, 10% away, which is inside the ±5% band of neither part but close enough to substitute in most non-critical positions.
The same resistor as a surface-mount marking
Surface-mount resistors have no room for bands, so they carry printed digits instead — and 304 is what 300 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 |
|---|---|---|
304 | Three-digit, ±5% parts | 30 followed by 4 zeros |
3003 | Four-digit, ±1% parts | 300 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 304 and 3003 are the same 300 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 300 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 300 kΩ resistor?
orange black yellow gold on a four-band resistor: orange for 3, black for 0, yellow for a multiplier of ×10,000, and gold for ±5%.
What resistor is orange black yellow gold?
300 kΩ, ±5%. The first two bands are the digits 3 and 0, the third multiplies by 10,000, and the gold band is the tolerance.
What is the tolerance range of a 300 kΩ ±5% resistor?
285 kΩ to 315 kΩ. A resistor measuring anywhere in that range is within specification, which is why a meter reading of 285 kΩ on a 300 kΩ part is not a fault.
What is the five-band code for 300 kΩ?
orange black black orange brown — three digit bands (3, 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
- 330 kΩ resistor colour code — orange orange yellow gold
- 360 kΩ resistor colour code — orange blue yellow gold
- 390 kΩ resistor colour code — orange white yellow gold
- 430 kΩ resistor colour code — yellow orange yellow gold
- 470 kΩ resistor colour code — yellow violet yellow gold
- 510 kΩ resistor colour code — green brown yellow gold
- 560 kΩ resistor colour code — green blue yellow gold
- 620 kΩ resistor colour code — blue red yellow gold
- 680 kΩ resistor colour code — blue grey yellow gold
- 750 kΩ resistor colour code — violet green yellow gold