Resistor Color Code
Decode 4-band resistor color codes or enter a value to see the corresponding bands.
Resistor Color Code
Results
4-Band Resistor
How to read resistor color codes
When to use this: Use this to quickly decode the color bands on a through-hole resistor, or to find the color bands for a value you need to source. Supports 4-band (standard ±5%) and 5-band (precision ±1%) resistors, plus SMD markings.
Resistors are too small to print their value as a number, so manufacturers paint colored bands on the body instead. Each color maps to a digit (0–9) or a multiplier, and the system has been standardized since the 1950s. Reading color codes is a daily skill for anyone working with through-hole components — even with a multimeter handy, it's faster to read the bands than to probe.
For a 4-band resistor: bands 1 and 2 are the first two significant digits, band 3 is the multiplier (the power of 10), and band 4 is the tolerance. Hold the resistor so the tolerance band (gold or silver) is on the right — there's usually a wider gap before it. Red-Red-Brown-Gold reads as 2, 2, ×10, ±5% = 220Ω ±5%.
5-band resistors use three significant digits instead of two. Brown-Black-Black-Red-Brown = 1, 0, 0, ×100, ±1% = 10,000Ω. These are precision metal film resistors, typically ±1% tolerance, and they come in the E96 series which has 96 values per decade instead of E24's 24. You'll see them wherever accuracy matters — filter networks, instrumentation, op-amp gain resistors.
The tolerance band matters more than people think. A 100Ω ±5% resistor can measure anywhere from 95Ω to 105Ω. In a voltage divider or filter, that translates directly to output error. Use ±1% resistors whenever the circuit's performance depends on matching or precision — they cost only marginally more and are always worth it in those cases.
For SMD resistors, the code is different. A 3-digit code like '103' means 10 × 10³ = 10kΩ. A 4-digit code like '1002' means 100 × 10² = 10kΩ with better precision. The last digit is always the number of zeros to append. Tiny 0402 and 0201 packages often print nothing at all — you need a multimeter or the reel label.
4-Band Formula
R = (10·B1 + B2) × 10^B3Color Reference
Practical Examples
220 Ω resistor commonly used with LEDs on 5V Arduino/Raspberry Pi.
Red–Red–Brown–Gold = 220 Ω ±5%
10 kΩ is the standard I2C pull-up and GPIO pull-up value for 3.3V/5V systems.
Brown–Black–Orange–Gold = 10 kΩ ±5%
4.7 kΩ used in voltage dividers, ADC inputs, and transistor biasing circuits.
Yellow–Violet–Red–Gold = 4.7 kΩ ±5%
Common Values Reference
| Value | Color Code (4-band, ±5%) | Common Use |
|---|---|---|
| 100 Ω | Brown–Black–Brown–Gold | Current limiting, base resistors |
| 220 Ω | Red–Red–Brown–Gold | LED current limit at 5V (20mA) |
| 470 Ω | Yellow–Violet–Brown–Gold | LED current limit at 12V, snubbers |
| 1 kΩ | Brown–Black–Red–Gold | Pull-down, base bias, general |
| 4.7 kΩ | Yellow–Violet–Red–Gold | Voltage divider, bias networks |
| 10 kΩ | Brown–Black–Orange–Gold | I2C pull-up, ADC divider |
| 47 kΩ | Yellow–Violet–Orange–Gold | High-impedance feedback |
| 100 kΩ | Brown–Black–Yellow–Gold | Op-amp feedback, timing |
Memory trick: the color code mnemonic
The standard order — Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White (0–9) — can be remembered with these mnemonics:
"Better Be Right Or Your Great Big Venture Goes Wrong"
B=Black, B=Brown, R=Red, O=Orange, Y=Yellow, G=Green, B=Blue, V=Violet, G=Grey, W=White
"No Busques Razones, Oye, Ya Que Antes Vivías Gratis"
N=Negro, B=Marrón, R=Rojo, O=Naranja, A=Amarillo, V=Verde, A=Azul, V=Violeta, G=Gris, B=Blanco
SMD resistor codes (surface mount)
Surface-mount resistors don't use color bands. Instead they print a numeric code directly on the component body. Two systems are in use:
| Code | System | Reading | Value |
|---|---|---|---|
| 103 | 3-digit EIA | 10 × 10³ | 10 kΩ |
| 472 | 3-digit EIA | 47 × 10² | 4.7 kΩ |
| 1002 | 4-digit EIA | 100 × 10² | 10 kΩ (1% precision) |
| 4991 | 4-digit EIA | 499 × 10¹ | 4.99 kΩ (1% precision) |
| 01C | EIA-96 | Lookup table | 1.00 kΩ ±1% |
| R47 | Sub-ohm | R = decimal point | 0.47 Ω |
The last digit in the EIA system is always the exponent (number of zeros to append). So 473 = 47,000Ω = 47kΩ. Sub-ohm resistors use 'R' as the decimal point: 4R7 = 4.7Ω, R100 = 0.1Ω. Tiny 0402 and 0201 packages often have no marking at all.
E24 vs E96: why your exact value doesn't exist
Resistors come in standardized series with a fixed number of values per decade. The E24 series has 24 values per decade (±5% tolerance), covering 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0... up to 9.1. The E96 series has 96 values per decade (±1% tolerance), and can hit almost any target value within 1%.
This is why there is no exact 1500Ω in the E24 series — the closest values are 1.5kΩ and 1.6kΩ. If you need exactly 1500Ω, use E96 (which has 1500Ω) or combine two E24 values: 1.2kΩ + 300Ω = 1500Ω in series.
Complete color code reference table
| Color | Digit | Multiplier | Tolerance | Temp Coef (ppm/°C) |
|---|---|---|---|---|
| Black | 0 | ×1 | — | 250 |
| Brown | 1 | ×10 | ±1% | 100 |
| Red | 2 | ×100 | ±2% | 50 |
| Orange | 3 | ×1k | — | 15 |
| Yellow | 4 | ×10k | — | 25 |
| Green | 5 | ×100k | ±0.5% | 20 |
| Blue | 6 | ×1M | ±0.25% | 10 |
| Violet | 7 | ×10M | ±0.1% | 5 |
| Grey | 8 | ×100M | ±0.05% | 1 |
| White | 9 | ×1G | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
4-band vs 5-band vs 6-band resistors
4-band resistors are the most common type found in general-purpose circuits. They encode two significant digits, a multiplier, and a tolerance band (Gold ±5% or Silver ±10%). If you are building a hobby project, power supply filter, or basic audio circuit, 4-band resistors are almost always the right choice. They are cheap, stocked everywhere, and easy to read by eye.
5-band resistors encode three significant digits and are used for precision applications such as measurement circuits, audio amplifiers, and instrumentation — typically with ±1% (Brown) or ±2% (Red) tolerance. 6-band resistors add a sixth band that specifies the temperature coefficient (tempco) in ppm/°C. The 6th band allows you to predict how much the resistance will drift with temperature, which is critical for industrial calibration equipment and military-spec circuits where stable readings across −55°C to +125°C are required.
Did you know? The resistor color code was standardized by the EIA in the 1920s. The colors were chosen partly for visibility under factory lighting conditions — which is why red, orange, and yellow were favoured over lighter hues.