Resistor Color Code Calculator
Resistor Color Code Calculator
Read a resistor from its color bands on 3, 4, 5 or 6 band parts, or find the bands for a value. It shows the tolerance range, whether the value is a standard E series number, the nearest standard values, and decodes SMD codes including EIA 96.
Where the value sits among the E series
Resistance = (digits as a number) × multiplier, read from the band nearest an end, with the tolerance band last. Colors follow IEC 60062:2016 and standard values follow IEC 60063. Minimum and maximum are the nominal value × (1 − tolerance) and × (1 + tolerance). Every SMD code is read as digits and a multiplier, or as R, K and M notation, or as EIA 96. The CSV, image and printed report contain the values you entered, nothing preloaded.
How to use this tool
Pick what you want to do. "Bands to value" asks for the number of bands and the color of each one in reading order: the digits, then the multiplier, then the tolerance, and on a six band part the temperature coefficient. "Value to bands" takes a resistance, a unit, the number of bands and a tolerance, and shows the colors. "SMD code" reads and writes the characters printed on chip resistors, including the EIA 96 system, and "Color and series tables" shows the whole color code or any E series with band colors.
The input people most often get wrong is the starting end. Read from the band that sits closest to an end of the body, with the wider gap, and usually a gold or silver band, on the right. The next is the unit box in value mode: 4.7 with kΩ selected is 4,700 Ω, while 4.7 with Ω selected is 4.7 Ω. If the exact value cannot be shown in the bands you chose, the tool says so and gives the nearest one, the error in percent, and the standard values on either side. It reads standard IEC codes only, so military, vintage and maker specific schemes are outside it.
What the calculation is doing
A four band resistor holds two significant digits, a multiplier and a tolerance. Yellow, violet, red, gold is 4 and 7, so 47, times 100, which is 4,700 Ω or 4.7 kΩ at ±5%. A five band resistor holds three digits: yellow, white, white, brown, brown is 499 × 10 = 4,990 Ω at ±1%. A three band part has no tolerance band and counts as ±20%. A six band part adds a temperature coefficient in ppm/K, parts per million of resistance per kelvin: brown is 100, so a 4.7 kΩ part can move by 0.47 Ω for each kelvin.
The minimum and maximum are the nominal value times (1 − tolerance) and (1 + tolerance): 4,700 × 0.95 = 4,465 Ω and 4,700 × 1.05 = 4,935 Ω. Going the other way, the tool rounds your value to the digits the bands can hold, and when the rounded value differs it reports the error as (shown − asked) ÷ asked. For SMD marking, a 3 digit code is two digits and a power of ten (472 is 47 × 10² = 4.7 kΩ), and a 4 digit code is three digits and a power of ten (1002 is 100 × 10² = 10 kΩ). R marks a decimal point, so 4R7 is 4.7 Ω. EIA 96 is a two digit position in the E96 list plus a multiplier letter, so 01C is 100 × 100 = 10 kΩ.
Which end to read from
The standard asks for the first band to be the one nearest to an end of the resistor, and for the tolerance band to be at least 1.5 times as wide as the others. On most parts the tolerance band is also set apart, so the gap before it is bigger than the gaps between the digits. When the printing is good that is all you need: the band that stands apart belongs on the right.
Trouble starts when the layout gives no help, for example bands spaced evenly, or a five band part whose tolerance band is brown, the same color as a digit. Three checks settle most cases. Gold and silver are never digits, so a gold or silver band is the tolerance. Black and white are never tolerances, and a black first band is not used, so a reading that needs them there is wrong. And a wrong direction tends to give an absurd value: read backwards, yellow, white, white, brown, brown becomes brown, brown, white, white, yellow, which is 119 GΩ at ±0.02%, and no shelf part is that.
When both directions give a plausible number, use the E series as the tiebreaker. A ±1% resistor should carry an E96 or E192 value, so of two readings the one that lands on a listed value is the better bet. The tool shows the series a value belongs to and warns when a ±1% reading falls outside E96 and E192. If that still leaves doubt, measure the part out of circuit.
Why standard values are spaced by a ratio
Standard values are not evenly spaced because tolerance is a percentage. A ±10% resistor of 1 kΩ can be anywhere from 900 Ω to 1,100 Ω, while a ±10% resistor of 100 kΩ spans 90 kΩ to 110 kΩ. Steps that grow in proportion to the value use the tolerance equally at every size. So the IEC 60063 series step by a fixed ratio: the 12th root of 10 for E12, the 24th for E24, the 96th for E96.
For E12 the ratio is 1.2115. With ±10%, the range of one value reaches 1.10 times itself, and the range of the next starts at 0.90 × 1.2115 = 1.0904 times the first, so the two ranges overlap by 0.96%. E24 at ±5% overlaps by 0.43%. From E48 up the usual tolerance is a little too tight to touch: E96 at ±1% leaves a gap of 0.40% between neighboring ranges, and E192 at ±0.5% leaves 0.20%. The table gives every series, with the numbers as a percentage of the value.
| Series | Values per decade | Step ratio | Usual tolerance | Neighboring ranges |
|---|---|---|---|---|
| E6 | 6 | ×1.4678 | ±20% | overlap 2.58% |
| E12 | 12 | ×1.2115 | ±10% | overlap 0.96% |
| E24 | 24 | ×1.1007 | ±5% | overlap 0.43% |
| E48 | 48 | ×1.0491 | ±2% | gap 0.82% |
| E96 | 96 | ×1.0243 | ±1% | gap 0.4% |
| E192 | 192 | ×1.0121 | ±0.5% | gap 0.2% |
The published lists are not simply 10 to the power k ÷ N, rounded. E48, E96 and E192 follow that rule, with one exception in E192: the standard prints 9.20 where rounding gives 9.19. E6, E12 and E24 carry hand set values such as 3.3 and 4.7, where rounding gives 3.2 and 4.6. That is why the tool holds the published lists as tables and does not calculate them.
The spacing also explains why a four band code cannot show 4.99 kΩ. Two digits reach 4.9 and 5.0, so the closest is 5 kΩ, 0.2% high. E24 values fit in two digits by design, while E96 values need three, which is why ±1% resistors carry five bands.
What 1 percent really means in a divider
A tolerance is a bound, not a typical error, and two of them do not always add. Put two 10 kΩ resistors in a divider across 10 V, which should give 5 V. With ±1% parts the worst case is one resistor 1% high and the other 1% low, and the output is 10 × 10.1 ÷ 20 = 5.05 V or 4.95 V. That is ±1% on the output, not ±2%, because the resistor that gets bigger and the one that gets smaller move the total very little. With ±5% parts the same arithmetic gives 4.75 V to 5.25 V.
Temperature adds its own error, and a six band part is the only one where the color code says how much. At 100 ppm/K a 10 kΩ resistor changes by 1 Ω for every kelvin, so a 40 K rise moves it by 40 Ω, or 0.4%. That is comparable to the tolerance of a ±1% part. The tolerance band says nothing about temperature, load or age, only the spread at the reference conditions in the datasheet.
Carbon film, metal film and the colors you see
There is a pattern in the parts sold in kits: many carbon film resistors are four band ±5% parts, and many metal film resistors are five band ±1% parts. Treat that as a habit, not a rule. The standard ties neither the number of bands nor the color of the body to the material. Carbon composition resistors were sorted to 5% at best, and metal film is commonly 0.5%, 1% or 2% with a temperature coefficient of 50 to 100 ppm/K, according to the Wikipedia article on resistors.
So a gold band tells you the tolerance and nothing more. If temperature behavior matters, look for a sixth band or the datasheet, and do not infer the construction from the body color or the band count.
The color code and the EIA 96 letters
The color code below follows IEC 60062:2016, generated from the same table the tool uses. Orange, yellow and gray as tolerances (±0.05%, ±0.02% and ±0.01%) and pink as the multiplier ×0.001 are 2016 assignments, and some older charts and makers use gray for ±0.05%.
| Color | Digit | Multiplier | Tolerance | ppm/K |
|---|---|---|---|---|
| Black | 0 | ×1 | none | 250 |
| Brown | 1 | ×10 | ±1% | 100 |
| Red | 2 | ×100 | ±2% | 50 |
| Orange | 3 | ×1k | ±0.05% | 15 |
| Yellow | 4 | ×10k | ±0.02% | 25 |
| Green | 5 | ×100k | ±0.5% | 20 |
| Blue | 6 | ×1M | ±0.25% | 10 |
| Violet | 7 | ×10M | ±0.1% | 5 |
| Gray | 8 | ×100M | ±0.01% | 1 |
| White | 9 | ×1G | none | none |
| Gold | none | ×0.1 | ±5% | none |
| Silver | none | ×0.01 | ±10% | none |
| Pink | none | ×0.001 | none | none |
| No band | none | none | ±20% | none |
For SMD parts marked in the EIA 96 system, the second half of the code is a letter. The full list of 96 code numbers is shown in the tool when you choose SMD code and EIA 96.
| Letter | Multiplier | Example |
|---|---|---|
| Z | ×0.001 | 01Z = 100 × 0.001 = 0.1 Ω |
| Y or R | ×0.01 | 01Y = 100 × 0.01 = 1 Ω |
| X or S | ×0.1 | 01X = 100 × 0.1 = 10 Ω |
| A | ×1 | 01A = 100 × 1 = 100 Ω |
| B or H | ×10 | 01B = 100 × 10 = 1 kΩ |
| C | ×100 | 01C = 100 × 100 = 10 kΩ |
| D | ×1k | 01D = 100 × 1k = 100 kΩ |
| E | ×10k | 01E = 100 × 10k = 1 MΩ |
| F | ×100k | 01F = 100 × 100k = 10 MΩ |
A worked example you can check on paper
The default view is a four band resistor: yellow, violet, red, gold. Digits: yellow = 4, violet = 7, so 47. Multiplier: red = ×100, so 47 × 100 = 4,700 Ω = 4.7 kΩ. Tolerance: gold = ±5%, so 4,700 × 0.05 = 235 Ω, and the value lies between 4,465 Ω and 4,935 Ω. Series: 4.7 is in E6, E12, E24 and E192, but not E96, whose neighbors are 4.64 and 4.75.
The reverse direction for a five band part: 4.99 kΩ at ±1%. 4.99 kΩ = 499 × 10 Ω, so the digits 4, 9, 9 are yellow, white, white, the multiplier ×10 is brown, and ±1% is brown. Four bands would round to 5.0 kΩ = 50 × 100, which is green, black, red, and (5,000 − 4,990) ÷ 4,990 = 0.2% too high.
For SMD, 4.7 kΩ is written 472 (47 × 10²) or 4701 (470 × 10¹) and as 4K7 in RKM notation. Because 4.7 kΩ is not an E96 value it has no exact EIA 96 code, and the nearest is 4.75 kΩ, which is 66B: code 66 is 475 and B is × 10.
Mistakes that catch people out
Starting from the wrong end. Read backwards, a common value turns into nonsense or into a different plausible one. Start at the end nearest a band, keep the gap and any gold or silver band on the right, and check the result against the E series.
Mixing brown, red and orange. Dark brown looks like red, and red looks like orange under warm light. Old resistors also darken. Look in daylight or with a white LED, and when in doubt, measure the part with a multimeter.
Miscounting the bands. Count them before you read. A four band part has two digits, a multiplier and a tolerance, while a five band part has three digits. Treating a five band part as four bands drops a digit and gives a value about ten times off.
Trusting a value that is not standard. A ±5% resistor of 4.8 kΩ is not an E24 value, so one of the colors is probably misread. The series line in the results catches this, and so does the nearest standard value in value mode.
Assuming gray means ±0.05%. The current standard gives gray ±0.01%, and this tool follows it, so for a gray, orange or yellow tolerance band check the datasheet.
Popular calculations
Each one opens the calculator with those figures filled in.
Common values, bands to value
Common values, value to bands
Five and six band precision resistors
Values four bands cannot show exactly
SMD codes
Color code and E series tables
How this was checked
The color table was compared value by value with Table 1 of IEC 60062:2016 for all 13 colors (digit, multiplier, tolerance and temperature coefficient), and with Wikipedia's transcription of the same edition. The engine lists for E6, E12, E24, E48, E96 and E192 equal the published IEC 60063 lists as printed on Wikipedia. E6, E12, E24 and E192 also equal Vishay document 28372, and E96 equals the 96 base values of a published EIA 96 code table. E96 is every second E192 value and E48 every fourth, as the standard structure requires.
Independent routes were used on top of that. Every E24 value from 10 Ω to 10 MΩ was turned into bands and read back in four and five band form (292 cases), and every E96 value in five band form (577 cases), and all returned exactly the same value. All 90 six band combinations of tolerance and temperature coefficient read back correctly. The nearest representable value matched an exhaustive search on 3,000 random values, with errors within 5% for four bands and 0.5% for five. For SMD codes, 28 published examples from JLCPCB, EEPower, Panasonic, mikrocontroller.net and IEC 60062 decoded as published, and all 864 EIA 96 codes and 7,920 digit codes round tripped in both directions. Every address in the lists above was opened and checked for a distinct title and a chart that renders.
Common questions
How do you read a resistor color code?
Hold the resistor so the band nearest an end is on the left and the wider gap is on the right. Read the first two bands (three on a five band part) as digits, the next band as the multiplier, and the last as the tolerance. Yellow, violet, red, gold is 4 and 7, times 100, so 4,700 Ω or 4.7 kΩ at ±5%.
Which end do you start reading from?
The end closest to a band. The standard asks for the first band to be nearest an end and the tolerance band to be at least 1.5 times as wide as the others. Gold and silver are never digits, so if one of them is at an end, that end is the right hand end. If both directions give a plausible number, prefer the one that is a standard value.
What is the difference between a 4 band and a 5 band resistor?
A four band code carries two significant digits and a five band code carries three, so five bands can show values such as 4.99 kΩ that four bands can only round to 5 kΩ. Five band parts are typically used for ±1% and tighter tolerances, whose values come from the E96 and E192 series. Both end in a tolerance band, and a six band part adds a temperature coefficient.
What do the E12, E24 and E96 series mean?
They are the preferred values of IEC 60063: 12, 24 or 96 values per decade, each about the same percentage above the last. E12 goes with ±10% parts, E24 with ±5% and E96 with ±1%. A 4.7 kΩ resistor is in E12 and E24, while its E96 neighbors are 4.64 kΩ and 4.75 kΩ.
How do you read an SMD resistor code such as 472 or 01C?
A three digit code is two digits and a power of ten, so 472 is 47 × 10² = 4.7 kΩ. A four digit code has three digits, so 1002 is 100 × 10² = 10 kΩ. R marks a decimal point, so 4R7 is 4.7 Ω. Two digits and a letter, such as 01C, is EIA 96: 01 stands for 100 in the E96 list and C is × 100, giving 10 kΩ.
What if the colors are faded or I cannot tell them apart?
Do not guess. Dark brown, red and orange blur together in poor light, and old parts darken. Measure the resistor with a multimeter with the part out of the circuit, then use the tool to find which color combination matches the reading and the nearest standard value.
Related Calculators and Reference
- Ohm Law Calculator: voltage, current, resistance and power once you know the resistor value.
- Watts to Amps Calculator: the current behind a power figure, for checking how much a resistor must dissipate.
- Scientific and Engineering Notation Converter: move between Ω, kΩ, MΩ and powers of ten.
- Percentage Calculator: percent error and percent difference for the tolerance arithmetic.
- Significant Figures and Rounding Calculator: rounding to two or three digits, as the bands do.
- IEC 60062:2016: the standard behind the color code and the marking codes, from the IEC store.