Works in both directions
Read the colors off a physical resistor, or type a target value like 4k7 and get the exact bands to look for in your parts drawer. No second tool needed.
Free Electronics Tool
Resistor Color Code Calculator
Decode any 3, 4, 5 or 6 band resistor in seconds, or work backwards from a resistance value to the exact band colors. This resistor color code calculator also reads SMD chip codes, shows the tolerance range and tells you whether your value is a standard E-series part.
3 to 6 bandsReverse lookupSMD code decoderE12 / E24 / E96 checkNo sign-up
Resistor Decoder
Tip: hold the resistor with the tolerance band (gold or silver) on the right, then read the bands from left to right.
1.0 kΩ±5%
Accepts plain ohms (470), decimals (4.7k), engineering notation (4k7, 2R2) and megohms (1M). Range: 0.1 Ω to 99 GΩ.
4.7 kΩ±5%
Supports 3 digit, 4 digit, R notation (4R7 = 4.7 Ω) and the EIA-96 system used on 1% chip resistors (01B = 1 kΩ).
4.7 kΩ3 digit
Why this resistor color code calculator is different
Most band charts online do one job badly. This one covers the whole workflow a technician, student or hobbyist actually needs at the bench.
3, 4, 5 and 6 band support
Handles legacy 3 band parts, everyday 4 band carbon film, precision 5 band metal film and 6 band resistors with a temperature coefficient band.
SMD chip code decoder
Surface mount markings use a different system entirely. The third tab decodes 3 digit, 4 digit, R notation and EIA-96 codes instantly.
Real tolerance range
A 1 kΩ ±5% resistor is legally anything from 950 Ω to 1.05 kΩ. The minimum and maximum are shown so you can judge whether a measured reading is in spec.
E-series verification
Every result is checked against the E12, E24 and E96 preferred value series, so you instantly know if the value is a stocked standard part or an unusual one.
Fast, private and free
Everything runs in your browser with no libraries, no accounts and no data sent anywhere. It loads in a fraction of a second, even on workshop Wi-Fi.
How to read a resistor color code
Orient the resistor
Put the tolerance band on the right. It is usually gold or silver, sits slightly apart from the others and is often wider. Now read left to right.
Count the bands
Choose 3, 4, 5 or 6 above to match your part. Four bands means two significant digits; five and six bands mean three digits and tighter precision.
Select each color
Set every dropdown to the color you see. The diagram updates live, so you can compare it with the resistor in your hand before trusting the number.
Read the result
The resistance appears in ohms, kilohms or megohms with the tolerance range. Copy it, or switch tabs to work backwards from a value you need.
Resistor color code chart
The full band reference. Digit columns apply to the first two or three bands, the multiplier column to the band before the tolerance band.
| Color | Digit | Multiplier | Tolerance | Temp. coefficient |
|---|---|---|---|---|
| Black | 0 | × 1 Ω | — | 250 ppm/K |
| Brown | 1 | × 10 Ω | ±1% | 100 ppm/K |
| Red | 2 | × 100 Ω | ±2% | 50 ppm/K |
| Orange | 3 | × 1 kΩ | — | 15 ppm/K |
| Yellow | 4 | × 10 kΩ | — | 25 ppm/K |
| Green | 5 | × 100 kΩ | ±0.5% | 20 ppm/K |
| Blue | 6 | × 1 MΩ | ±0.25% | 10 ppm/K |
| Violet | 7 | × 10 MΩ | ±0.1% | 5 ppm/K |
| Grey | 8 | × 100 MΩ | ±0.05% | 1 ppm/K |
| White | 9 | × 1 GΩ | — | — |
| Gold | — | × 0.1 Ω | ±5% | — |
| Silver | — | × 0.01 Ω | ±10% | — |
| None | — | — | ±20% | — |
Who this tool helps
Electronics students checking homework and lab work without memorising the whole color chart on day one.
Hobbyists and makers sorting a mixed bag of resistors for an Arduino, Raspberry Pi or guitar pedal build.
Repair technicians identifying a burnt or discoloured part where one band is hard to read and the range matters.
PCB designers confirming that a calculated value exists as a real E24 or E96 part before releasing a bill of materials.
Anyone working with SMD boards who needs to translate a tiny printed code into an actual resistance value.
Teachers and trainers demonstrating how the band system encodes digits, multipliers and precision.
Frequently asked questions
How do I read a 4 band resistor color code?
Place the gold or silver tolerance band on the right. The first band is the first digit, the second band is the second digit, the third band is the multiplier and the fourth is the tolerance. Brown, black, red, gold reads as 1, 0, × 100, ±5%, which is 1000 Ω or 1 kΩ with a 5% tolerance.
What is the difference between 4 band and 5 band resistors?
A 4 band resistor encodes two significant digits and is typically a 5% or 10% carbon film part. A 5 band resistor encodes three significant digits, which allows tighter values such as 4.75 kΩ, and is normally a 1% or better metal film part. A sixth band, when present, gives the temperature coefficient in parts per million per kelvin.
Which end of the resistor do I start reading from?
Start from the end where the bands are grouped closest together. The tolerance band sits on the opposite end with a visibly wider gap before it, and it is gold or silver on most common parts. If both ends look identical, read it in both directions and pick the one that lands on a standard E-series value, which this calculator flags for you.
What does the gold band on a resistor mean?
Gold has two meanings depending on its position. As the final band it means a tolerance of ±5%. As the multiplier band it means multiply by 0.1, which is how sub-ohm values such as 0.47 Ω are written. Silver works the same way: ±10% as a tolerance, or × 0.01 as a multiplier.
Why does my multimeter reading not match the color code?
A small difference is expected. The color code gives a nominal value and the tolerance band gives the permitted spread around it, so a 1 kΩ ±5% part measuring 968 Ω is perfectly in spec. Also check that the resistor is out of circuit, since parallel paths on a live board pull the reading down, and remember that test lead resistance matters on very low values.
How do I read the code on an SMD resistor?
Surface mount resistors are printed, not banded. A 3 digit code such as 472 means the first two digits followed by that many zeros, giving 4700 Ω. A 4 digit code such as 4701 uses three digits plus a multiplier. An R marks the decimal point, so 4R7 is 4.7 Ω. Precision 1% parts use EIA-96, a two digit lookup code plus a multiplier letter, which the SMD tab of this tool decodes for you.
What are E12, E24 and E96 resistor values?
They are the preferred value series that manufacturers actually stock. E12 has 12 values per decade and suits 10% parts, E24 has 24 values and suits 5% parts, and E96 has 96 values for 1% precision resistors. If a value you calculate is not in any series, you will need to combine resistors or move to the nearest available part.
Can a resistor color code have only three bands?
Yes. Three band resistors give two digits and a multiplier but no tolerance band, which by convention means ±20%. They are mostly found in older equipment and low-cost assemblies. Select the 3 band option above and the calculator applies the ±20% assumption automatically.
Decode any resistor in under five seconds
Bookmark this page and keep it open next to your bench. Whether you are reading bands off a through-hole part, hunting for a specific value in a parts bin or squinting at an SMD chip, the answer is three clicks away.