Resistor Color Code Decoder

{{ error }}

Band count:

Use 4 for common carbon-film parts, 5 for precision parts, and 6 when a temperature coefficient band is present.

{{ slot.label }}:

Temperature change: {{ boundedTemperatureDelta }} deg C

Estimate drift for a bench-to-operating temperature change.

deg C

Examples:

Use a known code to verify the decoder before entering your own band colors.

Load sample

Display precision: {{ precisionDigits }} digits

Use fewer digits for quick bench reading or more when documenting precision parts.

Band role	Color	Code	Contribution	Copy
{{ row.role }}	{{ row.color }}	{{ row.code }}	{{ row.contribution }}

Quantity	Value	Detail	Copy
{{ row.label }}	{{ row.value }}	{{ row.detail }}

Check	Status	Detail	Copy
{{ row.label }}	{{ row.value }}	{{ row.detail }}

Color	Digit	Multiplier	Tolerance	TCR	Copy
{{ row.color }}	{{ row.digit }}	{{ row.multiplier }}	{{ row.tolerance }}	{{ row.tcr }}

Export to PDF Fullscreen

Embed:

Customize

Include current inputs

Size

Advanced

Width

Height

Aspect ratio

Max height

Collapsible embed

Allow fullscreen

Referrer policy

Sandbox tokens

Resistor color bands are a compact marking system for leaded resistors. Instead of printing a long value on a small cylindrical body, the part uses bands for significant digits, a multiplier, a tolerance, and sometimes a temperature coefficient. Reading those bands correctly turns a physical component into a nominal resistance value and a realistic measurement window.

The band count matters because it changes how many significant digits are present. A common 4-band resistor uses two digit bands before the multiplier. A 5-band precision resistor uses three digit bands. A 6-band resistor adds a temperature coefficient band, usually written in parts per million per degree C, so the color code also gives a small thermal drift estimate.

Four, five, and six band resistor layouts showing digit, multiplier, tolerance, and temperature coefficient positions.

Color decoding is most useful before a resistor goes into a circuit, after an old part is pulled from equipment, or when a marked part has been separated from its bin label. The decoded value still needs judgment. Faded paint, unusual spacing, manufacturer-specific markings, heat damage, and in-circuit measurement paths can all make a neat band reading less reliable than it looks.

For bench work, the color code is a first pass. A digital multimeter reading inside the tolerance window confirms that the marked value and the actual part agree closely enough for the job.

How to Use This Tool:

Begin with the physical band layout, then choose the colors from left to right as you read the resistor.

Choose Band count. Use 4 band for two significant digits, 5 band for three significant digits, or 6 band when the part has a temperature coefficient band after the tolerance band.
Select each Band color in order. The color swatch beside each menu should match the part, and the resistor preview updates as the choices change.
If the layout is uncertain, use Examples to load a known pattern, then replace one band at a time. Gold and silver are valid multiplier or tolerance colors, but they are not valid digit colors.
For a 6-band resistor, set Temperature change to estimate drift over the temperature difference you care about. The value is clamped from 0 to 100 deg C.
Open Advanced only when the rounded display needs more or fewer digits. Display precision changes the summary, tables, chart labels, and structured output without changing the decoded resistance.
Read the summary first, then check Band Ledger, Tolerance Window, Tolerance Range Map, and Read Check. Read Check is the best place to verify orientation, first digit, tolerance class, and the expected DMM check range.

If an alert says a color is not valid for a band role, change that band to one of the listed colors for the active role. If Read Check marks First digit as Review, rotate the resistor and compare band spacing before trusting the value.

Interpreting Results:

The headline value is the nominal resistance implied by the selected bands. The more useful bench result is the tolerance window: a real resistor with that color code should measure between the lower and upper limits at room temperature, before circuit connections, self-heating, and measurement error are considered.

How to read resistor color code result fields
Output	Meaning	What to verify
Nominal resistance	The marked value before tolerance is applied.	Compare it with the value expected by the schematic or parts list.
Lower limit and Upper limit	The accepted range from the tolerance band.	A DMM reading inside this range supports the color reading; outside it, check orientation and remove the part from parallel circuit paths.
Tolerance spread	The plus-or-minus resistance difference around the nominal value.	Small percentage tolerances can still be large in ohms on high-value resistors.
Temperature coefficient	The 6-band drift rate in ppm/C and the estimated resistance change for the selected temperature change.	Treat it as a drift magnitude estimate, not as a full datasheet guarantee over humidity, voltage, aging, or power dissipation.
Orientation and First digit	Checks that help decide which end of the resistor should be read first.	Gold or silver near the tolerance end and a non-black first significant digit usually increase confidence.

A valid decode does not prove the part is electrically healthy. Confirm suspicious values with a meter, and isolate one resistor lead when surrounding circuit paths could place other resistances in parallel.

Technical Details:

Axial resistor color coding combines a decimal significant figure with a multiplier. The digit colors black through white represent 0 through 9. The multiplier band scales the significant figure by powers of ten, with gold and silver used for fractional multipliers. The tolerance band then states the symmetrical percentage range around the nominal resistance.

Four-band codes carry two significant digits, while five-band and six-band codes carry three. The sixth band is not another digit. It is a temperature coefficient of resistance, or TCR, expressed as parts per million per degree C. A 50 ppm/C part changes by about 50 millionths of its nominal value for each degree C, before any other real-world effects are considered.

Formula Core:

The nominal resistance is the significant number multiplied by the color multiplier. Tolerance and temperature drift are then calculated from that nominal value.

\begin{array}{rcl} R_{nom} & = & (10 d_{1} + d_{2}) M, for 4-band codes \\ R_{nom} & = & (100 d_{1} + 10 d_{2} + d_{3}) M, for 5-band and 6-band codes \\ R_{lower} & = & R_{nom} (1 - \frac{t}{100}) \\ R_{upper} & = & R_{nom} (1 + \frac{t}{100}) \\ R_{drift} & = & \frac{R_{nom} ppm ΔT}{1000000} \end{array}

Here, d values are digit colors, M is the multiplier, t is the tolerance percentage, ppm is the temperature coefficient, and delta T is the selected temperature change in deg C. For yellow, violet, black, brown, brown, red, the significant number is 470, the multiplier is 10, the tolerance is 1%, and the TCR is 50 ppm/C. That gives 4,700 ohm nominal, 4,653 ohm to 4,747 ohm by tolerance, and 5.875 ohm of estimated drift over 25 deg C.

Decoding Map:

The selectable color meanings are role-specific. A blank cell means that color is not offered for that role in the decoder.

Selectable resistor color code meanings
Color	Digit	Multiplier	Tolerance	TCR
Black	0	x1	-	-
Brown	1	x10	+/-1%	100 ppm/C
Red	2	x100	+/-2%	50 ppm/C
Orange	3	x1k	-	15 ppm/C
Yellow	4	x10k	-	25 ppm/C
Green	5	x100k	+/-0.5%	-
Blue	6	x1M	+/-0.25%	10 ppm/C
Violet	7	x10M	+/-0.1%	5 ppm/C
Gray	8	x100M	+/-0.05%	-
White	9	x1G	-	-
Gold	-	x0.1	+/-5%	-
Silver	-	x0.01	+/-10%	-

Band Arrangement:

Resistor band count arrangements
Band count	Value bands	Extra bands	Typical use
4 band	Band 1 digit, band 2 digit, band 3 multiplier	Band 4 tolerance	Common general-purpose axial resistors.
5 band	Bands 1 to 3 digits, band 4 multiplier	Band 5 tolerance	Precision parts where a third significant digit matters.
6 band	Bands 1 to 3 digits, band 4 multiplier	Band 5 tolerance, band 6 TCR	Precision parts where thermal drift is marked directly.

This decoder focuses on explicit 4-, 5-, and 6-band axial color codes. It does not model three-band parts with no tolerance band, surface-mount printed codes, body-end-dot vintage markings, military-specific variants, or manufacturer-only markings that require a datasheet.

Accuracy Notes:

Color bands describe the marked part, not the full operating condition of the circuit. Use the decoded value as a reading aid and pair it with measurement when the component is old, discolored, hot, physically damaged, safety-related, or still connected to other circuit paths.

Faded brown, red, orange, gray, and violet bands can be easy to confuse under poor light.
The tolerance window is symmetrical around the nominal value, but real drift over time, heat, and load stress can move a part outside that window.
The TCR estimate is based only on the marked ppm/C value and selected temperature change; it is not a substitute for a manufacturer datasheet.
In-circuit resistance readings can be pulled lower by parallel paths. Lift one lead when the meter result does not match the color code.

Worked Examples:

A common pull-up resistor marked brown, black, red, gold is a 4-band code. The digits are 10, the multiplier is x100, and the tolerance is +/-5%. Nominal resistance reads 1 kohm, Lower limit is 950 ohm, Upper limit is 1.05 kohm, and DMM check should accept a room-temperature reading inside that window.

A precision resistor marked brown, black, black, red, brown uses the 5-band layout. The first three bands form 100, red multiplies by 100, and brown sets +/-1%. Nominal resistance is 10 kohm, with Lower limit at 9.9 kohm and Upper limit at 10.1 kohm. The extra digit prevents reading the same pattern as a 1 kohm 4-band part.

For a six-band yellow, violet, black, brown, brown, red resistor, the value is 4.7 kohm +/-1%. With Temperature change set to 25 deg C, Temperature coefficient reports 50 ppm/C and about 5.875 ohm of estimated drift. That drift is smaller than the +/-47 ohm tolerance spread, but it can still matter in temperature-sensitive analog circuits.

A troubleshooting case starts with a suspicious first band. If a 4-band reading begins black, brown, red, gold, the decode can produce a value, but First digit reports Review. Rotate the part, look for the wider tolerance gap, and check whether gold or silver sits at the far end before using the result.

FAQ:

Why do 4-band and 5-band readings give different values?

The band count changes how many colors are read as significant digits. A 4-band code uses two digit bands before the multiplier, while a 5-band code uses three. Set Band count before selecting colors so Band Ledger assigns each band the right role.

Which end of the resistor should I start from?

Start from the end opposite the tolerance or TCR gap. Gold and silver usually appear near the tolerance end, and Read Check flags a black first significant digit as a reason to review the orientation.

Why are gold and silver missing from some band menus?

Gold and silver are selectable for multiplier and tolerance roles, not for digit roles. If a saved color set or manual edit puts one of those colors into a digit band, the alert asks you to choose a valid 0 to 9 digit color.

Does a 6-band TCR value replace the tolerance band?

No. In the 6-band layout, band 5 is still the tolerance band and band 6 is the temperature coefficient. Tolerance Window gives the lower and upper resistance limits, while Temperature coefficient estimates drift for the selected temperature change.

Does decoding send component data anywhere?

Band choices are decoded in the browser, and the page does not need photos, serial numbers, or account information. Avoid placing sensitive project labels in a shared URL or copied notes if you add that context outside the color-code fields.

Glossary:

Significant digit: The digit color that forms the leading number before the multiplier is applied.
Multiplier: The color band that scales the significant digits by a power of ten or by a fractional gold or silver multiplier.
Nominal resistance: The marked resistance value before tolerance, temperature drift, or aging effects are considered.
Tolerance: The allowed plus-or-minus percentage around the nominal resistance.
TCR: Temperature coefficient of resistance, the marked drift rate for a 6-band resistor.
ppm/C: Parts per million per degree C, used here to estimate resistance change from temperature change.

References:

IEC 60062:2016+AMD1:2019 CSV, Marking codes for resistors and capacitors, International Electrotechnical Commission, 2019-08-20.
IEC 60063:2015, Preferred number series for resistors and capacitors, International Electrotechnical Commission, 2015-03-27.
Resistor Color Code Calculator, Vishay.
Resistor colour code, Electronics Notes.