The 4 band resistor colour code is the universal visual language for through-hole resistors, standardized globally under IEC 60062. The system uses the first two bands for significant digits, the third band as a decimal multiplier, and the fourth band to indicate manufacturing tolerance. While surface-mount devices (SMD) rely on printed alphanumeric codes, the 4-band system remains the bench standard for prototyping, repair, and legacy equipment maintenance.
The Standard IEC 60062 Resistor Colour Code Table
To read this table correctly, identify the orientation of the resistor. The tolerance band (usually Gold or Silver) is spaced slightly further apart from the other three bands and is positioned on the far right when reading left-to-right. The first two columns apply strictly to the first two physical bands, the third column applies only to the third band, and the fourth column applies only to the final band.
| Colour | Band 1 (1st Digit) | Band 2 (2nd Digit) | Band 3 (Multiplier) | Band 4 (Tolerance) |
|---|---|---|---|---|
| Black | 0 | 0 | ×1 Ω | — |
| Brown | 1 | 1 | ×10 Ω | ±1% |
| Red | 2 | 2 | ×100 Ω | ±2% |
| Orange | 3 | 3 | ×1 kΩ | — |
| Yellow | 4 | 4 | ×10 kΩ | — |
| Green | 5 | 5 | ×100 kΩ | ±0.5% |
| Blue | 6 | 6 | ×1 MΩ | ±0.25% |
| Violet | 7 | 7 | ×10 MΩ | ±0.1% |
| Grey | 8 | 8 | ×100 MΩ | ±0.05% |
| White | 9 | 9 | ×1 GΩ | — |
| Gold | — | — | ×0.1 Ω | ±5% |
| Silver | — | — | ×0.01 Ω | ±10% |
Quick-Jump Common Values and Tolerance Variance
When designing or repairing circuits, you rarely calculate arbitrary values; you reach for standard E24 series values. The table below provides bookmark-friendly quick-jump rows for the most queried 4 band resistor colour code chart values encountered on the bench.
| Target Value | Band 1 | Band 2 | Band 3 | Band 4 | Real-World Range (±5%) |
|---|---|---|---|---|---|
| 100 Ω | Brown | Black | Brown | Gold | 95 Ω – 105 Ω |
| 220 Ω | Red | Red | Brown | Gold | 209 Ω – 231 Ω |
| 470 Ω | Yellow | Violet | Brown | Gold | 446 Ω – 493 Ω |
| 1 kΩ | Brown | Black | Red | Gold | 950 Ω – 1,050 Ω |
| 4.7 kΩ | Yellow | Violet | Red | Gold | 4,465 Ω – 4,935 Ω |
| 10 kΩ | Brown | Black | Orange | Gold | 9,500 Ω – 10,500 Ω |
| 100 kΩ | Brown | Black | Yellow | Gold | 95 kΩ – 105 kΩ |
What the Chart Cannot Tell You (Physical and Electrical Limits)
The 4 band resistor colour code chart is strictly a value-identification tool. It provides zero information about the component's physical limitations or construction type. Assuming a resistor can handle a circuit's demands based solely on its colour bands is a common cause of bench failures.
Power Rating and Physical Size
A 10 kΩ resistor with Brown-Black-Orange-Gold bands could be rated for 1/8W, 1/4W, 1/2W, or 2W. The colour code does not change; only the physical dimensions do. According to standard through-hole sizing guidelines, a 1/4W resistor typically features a body length of 6.3 mm and a diameter of 2.3 mm (often designated as size 0207 in metric axial specs). A 1/2W resistor jumps to 9.0 mm x 3.2 mm (size 0309). Always verify the physical size or the manufacturer's datasheet before pushing high current through an unverified axial lead.
Maximum Working Voltage
Every resistor has a maximum working voltage limit independent of its power dissipation. A standard 1/4W carbon film resistor is typically limited to 250V. If you place a 10 MΩ resistor across a 400V DC bus, the power dissipation is only 0.016W (well under the 0.25W thermal limit), but the 400V potential will exceed the dielectric breakdown voltage of the component's internal helical cut, leading to internal arcing and catastrophic failure.
Temperature Coefficient (TCR) and Inductance
The 4-band system omits the Temperature Coefficient of Resistance (TCR), which dictates how much the value drifts as the component heats up. If you need a low-TCR precision resistor (e.g., 50 ppm/°C), you must step up to a 5-band or 6-band resistor, or rely on SMD codes. Furthermore, the colour code cannot tell you if the resistor is wirewound (highly inductive, unsuitable for high-frequency RF or fast-switching snubber circuits) or metal film (low inductance).
Bench Verification and Measurement Techniques
While the 4 band resistor colour code chart is essential for initial sorting and schematic design, physical verification on the bench is mandatory for precision analog work. Carbon composition and thick-film resistors can drift significantly after years of thermal cycling or moisture ingress.
- Standard 2-Wire DMM Measurement: For resistors above 100 Ω, a standard digital multimeter using two test leads is perfectly adequate. Ensure your fingers are not touching the metal probes or the resistor leads simultaneously, as your body's parallel resistance (typically 50 kΩ to 500 kΩ depending on skin moisture) will skew readings on high-value resistors.
- Low-Value Shunt Measurement (<10 Ω): Standard multimeter leads introduce 0.2 Ω to 0.5 Ω of series resistance. If you are measuring a 0.22 Ω current-sense shunt resistor (Black, Red, Silver, Gold), the lead resistance will cause a massive measurement error. You must use a 4-wire (Kelvin) measurement setup or a dedicated milliohm meter to force current through one pair of leads and measure the voltage drop across a separate, high-impedance pair of sense leads.
- In-Circuit Measurements: Never trust a resistance reading taken while the component is soldered into a live or unpowered board. Parallel semiconductor junctions and alternative current paths will always yield a lower reading than the resistor's actual value. Desolder at least one leg of the resistor to isolate it from the circuit topology before measuring.
