Resistor color codes: read four and five bands

Find which end is first

Hold the resistor so its tolerance band is at the right. That band is often spaced farther from the digit bands and can be gold or silver, but spacing and color are not foolproof across manufacturers. Read the bands left to right only after identifying their roles. On some tiny, old, or unusual parts, pigment can be ambiguous or the marking scheme may differ. If the direction is uncertain, check the manufacturer's documentation or measure the isolated resistor rather than forcing a plausible color story.

Translate colors into digits

The common digit sequence is black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8, white 9. The first two bands of a four-band part give two significant digits; the first three of a five-band part give three. The following band multiplies that number by a power of ten: brown is ×10, red ×100, and black ×1. Gold used as a multiplier means ×0.1, not a significant digit. Read each band's position before using its color: the same brown can mean digit 1 or multiplier ×10.

Worked four-band example: brown black red gold

Brown and black give 1 and 0, so start with 10. Red as the third band is a ×100 multiplier: 10 × 100 Ω = 1,000 Ω, or 1 kΩ. The fourth gold band specifies ±5% tolerance, so a new, correctly specified part could be nominally acceptable from 950 Ω to 1,050 Ω at the specified test conditions. This is not a guarantee of its measured value in every circuit or at every temperature. A meter's own accuracy and contact resistance also affect a reading.

Worked five-band example: brown black black brown brown

The first three bands read 1, 0, 0: a significant-digit number of 100. The fourth brown band multiplies by ten, giving 100 × 10 Ω = 1,000 Ω. The last brown band is ±1% tolerance, which corresponds to 990–1,010 Ω around the nominal value under the specified conditions. Both examples decode to 1 kΩ, but they use different digit counts and tolerances. Do not confuse the fourth brown in this example with the tolerance brown at the end.

Debug a suspicious reading

If the bands appear to say 1 kΩ but the circuit behaves like a short or an open, switch power off and measure resistance with the part removed or at least one lead isolated. In-circuit parallel paths can produce a lower reading, while poor probe contact can make the reading unstable. Compare with your meter's range and the part's data sheet. Burned paint, lighting, and similar-looking brown, red, and orange bands are good reasons to measure rather than guess. A color code gives a nominal value and tolerance, not proof that a real part is intact.

1. Count bands and identify the likely tolerance end.
2. Decode significant digits, multiplier, and tolerance separately.
3. Isolate and measure the unpowered part if identification affects safety or diagnosis.