Resistor color bands turn a small component body into a compact value label. The reliable way to read one is to identify the band count first, find the end where the digit bands are grouped, and then apply the color table one role at a time. Start with the Resistor Color Code Calculator when you want to compare a visual reading with a calculated value.
Count the bands before reading them
Most through-hole resistors use three, four, five, or six colored bands. Three-band and four-band formats use two significant digits. Five-band and six-band formats normally use three significant digits. The band count changes the role of every mark after the digits, so do not decode a sequence until you know which format you are looking at.
| Band count | Band order | Typical tolerance | Extra information |
|---|---|---|---|
| 3-band | Digit 1, Digit 2, Multiplier | Not printed; commonly treated as +/- 20% | None |
| 4-band | Digit 1, Digit 2, Multiplier, Tolerance | Band 4 | None |
| 5-band | Digit 1, Digit 2, Digit 3, Multiplier, Tolerance | Band 5 | Three significant digits |
| 6-band | Digit 1, Digit 2, Digit 3, Multiplier, Tolerance, TCR | Band 5 | Temperature coefficient in ppm/K |
Find the correct reading direction
Start at the end where the significant-digit bands are grouped together and finish at the separated tolerance band. A wider gap often appears before tolerance. Gold and silver are common at the tolerance end, but tolerance can also be brown, red, orange, yellow, green, blue, violet, or grey. The first significant digit is normally not black, and gold, silver, and pink are not significant-digit colors.
Direction is a visual inference, not something this calculator can identify from a photograph. If both ends look plausible, enter each plausible order separately and compare the candidates with the schematic, bill of materials, expected circuit behavior, or an isolated meter reading.
Read digits and apply the multiplier
Black through white represent the digits 0 through 9. Gold is a x0.1 multiplier, silver is x0.01, and pink is x0.001 in tables that support it. For a three-band or four-band resistor, use this formula: (10 x digit 1 + digit 2) x multiplier. For five-band or six-band parts, use (100 x digit 1 + 10 x digit 2 + digit 3) x multiplier. The multiplier is a role, not a property of the color in every position.
Apply tolerance and temperature coefficient
A four-band example of brown, black, red, gold means 1 and 0 as the significant digits, red as x100, and gold as +/- 5 percent. That is 10 x 100 = 1,000 ohms, normally written as 1 kohm. The tolerance range is 950 to 1,050 ohms. A three-band brown, black, red has the same nominal value, but no separate tolerance band; it is commonly treated as +/- 20 percent for decoding. That is a convention, not proof of the physical part's manufacturing tolerance.
On a six-band resistor, the last band is temperature coefficient in parts per million per kelvin (ppm/K). It is not another multiplier and it does not change the nominal resistance. A lower TCR can matter in precision circuits, but the manufacturer datasheet controls when the color convention conflicts with a series-specific marking.
Worked resistor color code examples
| Marking | Format | Decoded result |
|---|---|---|
| Brown, Black, Red | 3-band | 1 kohm, commonly +/- 20% |
| Brown, Black, Red, Gold | 4-band | 1 kohm +/- 5% |
| Brown, Black, Red, Red | 4-band | 1 kohm +/- 2% |
| Brown, Black, Red, Silver | 4-band | 1 kohm +/- 10% |
| Brown, Black, Gold | 3-band | 1 ohm, commonly +/- 20% |
| Brown, Black, Gold, Gold | 4-band | 1 ohm +/- 5% |
| Red, Red, Silver | 3-band | 0.22 ohm, commonly +/- 20% |
| Orange, Orange, Brown, Gold | 4-band | 330 ohm +/- 5% |
| Yellow, Violet, Red, Gold | 4-band | 4.7 kohm +/- 5% |
| Brown, Black, Green, Gold | 4-band | 1 Mohm +/- 5% |
| Brown, Black, Red, Brown, Brown | 5-band | 1.02 kohm +/- 1% |
| Brown, Black, Red, Brown, Brown, Red | 6-band | 1.02 kohm +/- 1%, 50 ppm/K |
Reverse lookup: convert ohms to color bands
For reverse lookup, enter a value such as 4.7k, 1M, 4R7, or 1000. Three-band and four-band results use two significant digits; five-band and six-band results use three. The calculator returns a directly encodable candidate only when the value fits the selected format. For example, 4.7 kohm becomes yellow, violet, red, and gold in a four-band result. If tolerance is left empty for a four-, five-, or six-band reverse lookup, the current calculator uses gold, or +/- 5 percent, as its default. A reverse result is not an inventory lookup and does not guarantee a stocked E-series part.
Some values cannot be expressed exactly with two significant digits. A value such as 4,750 ohms needs more precision than a normal four-band code can show; a five-band code may express 4.75 kohm if the multiplier and significant digits fit. Do not silently round a requested value when the exact resistance matters.
When color bands are not enough
Faded, burned, dirty, or partly hidden bands create candidates rather than certainty. Record the possible colors, calculate each result, and compare with circuit documentation. A meter reading can also mislead when the resistor remains in parallel with another path, when the part is hot, or when the resistor has drifted. Remove power and isolate the part before relying on a resistance measurement.
Using the Resistor Color Code Calculator
Select three bands when the component has two digit bands and one multiplier. Select four bands when a separate tolerance band is visible. Select five or six bands when a third significant digit is present, then read tolerance and, for six bands, TCR. The tool updates as fields change; it does not identify direction, inspect a photograph, determine power rating, or replace a datasheet.
Frequently asked questions
Can the first band be black?
Not as the first significant digit in the common system, because that would create a leading zero. Recheck the reading direction or the condition of the marking.
Can gold or silver be the third band?
Yes. In a three-band or four-band code, gold and silver can be multipliers of x0.1 and x0.01. In a four-band code, a final gold or silver band can instead be tolerance, so the position matters.
Does a six-band resistor always use the same TCR table?
No. Common tables provide typical ppm/K mappings, but the series datasheet and manufacturer marking convention take priority.
Source and limits
This guide follows IEC 60062-style resistor color marking practice and the color/value conventions used in common through-hole manufacturer tables. Color decoding identifies the nominal marking; it does not prove that a particular part is genuine, undamaged, correctly installed, or available in the stated power rating.
- Use the Resistor Color Code Calculator as a reading aid, then compare the result with the component body, schematic, bill of materials, and datasheet.
- Gold, silver, faded paint, unusual spacing, and manufacturer-specific marks can create more than one plausible reading.
- Do not use a color-only result as a safety, installation, procurement, customs, or compliance decision.
Related guides
Resistor Color Code Chart explains each color; Which Way to Read a Resistor Color Code covers orientation; and Verify Resistor Value With a Multimeter covers an independent check.