A 4-band resistor uses the first two bands for significant digits, the third band for the decimal multiplier, and the fourth band for tolerance. To read any standard through-hole resistor, orient the component so the metallic or widely spaced tolerance band (usually gold or silver) is on the far right, then read the colors left-to-right. This system is globally standardized under IEC 60062, meaning a brown-black-red-gold resistor bought in Tokyo reads exactly the same as one bought in Texas: 1,000 ohms (1kΩ) with a ±5% tolerance.
The 4 Band Resistor Chart (IEC 60062 Standard)
The table below contains the complete color-to-value mapping as defined by the IEC 60062 international standard. Bookmark this section for quick bench reference.
| Color | Band 1 (1st Digit) | Band 2 (2nd Digit) | Band 3 (Multiplier) | Band 4 (Tolerance) |
|---|---|---|---|---|
| Black | 0 | 0 | ×1 (10⁰) | — |
| Brown | 1 | 1 | ×10 (10¹) | ±1% (F) |
| Red | 2 | 2 | ×100 (10²) | ±2% (G) |
| Orange | 3 | 3 | ×1k (10³) | — |
| Yellow | 4 | 4 | ×10k (10⁴) | — |
| Green | 5 | 5 | ×100k (10⁵) | ±0.5% (D) |
| Blue | 6 | 6 | ×1M (10⁶) | ±0.25% (C) |
| Violet | 7 | 7 | ×10M (10⁷) | ±0.1% (B) |
| Grey | 8 | 8 | — | ±0.05% (A) |
| White | 9 | 9 | — | — |
| Gold | — | — | ×0.1 (10⁻¹) | ±5% (J) |
| Silver | — | — | ×0.01 (10⁻²) | ±10% (K) |
Source: IEC 60062:2016 (Marking codes for resistors and capacitors). For deeper component theory, refer to the All About Circuits resistor guide.
How to Read the Table and Apply the Multiplier
When using this chart, the column that applies to your reading depends entirely on the band's physical position on the component body.
Worked Numeric Example: You are holding a resistor with Yellow, Violet, Red, Gold bands.
1. Band 1 (Yellow): 4
2. Band 2 (Violet): 7
3. Base Number: 47
4. Band 3 (Red): Multiplier is ×100 (or "add two zeros"). Result: 4,700 Ω (4.7kΩ).
5. Band 4 (Gold): Tolerance is ±5%.
Final Spec: A nominal 4.7kΩ resistor that the manufacturer guarantees to fall between 4,465 Ω and 4,935 Ω at room temperature.
How Derating and Tolerance Modify the Base Value: The tolerance band (Band 4) defines the absolute physical limits of the part at 25°C ambient. However, if your circuit operates in a high-temperature environment (e.g., inside an enclosed power supply), you must consult the manufacturer's power derating curve. Above 70°C ambient, the maximum allowable wattage drops linearly. While thermal derating doesn't change the nominal resistance, it forces a design change: if a 1/4W resistor must be derated to 0.1W due to heat, you must either select a larger physical package (like a 1W metal oxide) or alter your circuit topology to reduce current draw.
Bookmark-Friendly Quick-Jump: The Most Common Values
While the E12 and E24 series contain dozens of values, 90% of hobbyist and general commercial repair work relies on a small subset. Keep this quick-jump list handy to avoid counting bands on the most frequently used parts.
| Target Value | Band 1 | Band 2 | Band 3 (Multiplier) | Common Use Case |
|---|---|---|---|---|
| 100 Ω | Brown | Black | Brown (×10) | I2C pull-up (3.3V), current sensing |
| 220 Ω | Red | Red | Brown (×10) | Standard 5V LED current limiter |
| 330 Ω | Orange | Orange | Brown (×10) | Standard 5V LED (high brightness) |
| 1k Ω | Brown | Black | Red (×100) | General pull-down, base resistor for 2N2222 |
| 4.7k Ω | Yellow | Violet | Red (×100) | I2C pull-up (5V), generic biasing |
| 10k Ω | Brown | Black | Orange (×1k) | ESP32/Arduino GPIO pull-up, voltage dividers |
| 100k Ω | Brown | Black | Yellow (×10k) | Op-amp feedback, high-impedance pull-ups |
Decision Path: Identifying or Selecting Your Resistor
Use this decision tree to terminate your troubleshooting or design process with one concrete action.
| Scenario | If you observe / need... | Then take this concrete action |
|---|---|---|
| Reading a physical component | The bands are burnt, darkened, or the 4th band is missing. | Stop. Do not trust the color code. Carbonized resistors drop in value. Desolder one leg and measure with a multimeter, or trace the schematic for the design value. |
| Sorting a mixed bin | You cannot tell which end is Band 1. | Locate the Gold or Silver band. Place it on the far right. Read the remaining three bands left-to-right. |
| Designing an LED circuit | You need a current limiter for a standard red LED on a 5V Arduino pin (Target: 15mA). | Calculate: (5V - 2V) / 0.015A = 200Ω. Pick the next highest E12 standard value: Select a 220 Ω (Red-Red-Brown) 1/4W resistor. |
| Selecting for a power supply | The calculated wattage dissipation is 0.22W. | Do not use a standard 1/4W (0.25W) resistor; it will run too hot and drift. Pick a 1/2W (0.5W) metal film resistor to maintain a 50% safety margin. |
What the 4 Band Chart Cannot Tell You
The IEC 60062 color code strictly defines nominal resistance and manufacturing tolerance. It completely omits five critical parameters that will destroy your circuit if ignored:
- Power Rating (Wattage): The chart does not indicate wattage. You must read the physical dimensions. A standard 1/4W carbon/metal film resistor is roughly 6.3mm long and 2.5mm in diameter. A 1/2W resistor is ~9mm long and 3.5mm in diameter. Always verify the physical size against your calculated $I^2R$ losses.
- Maximum Working Voltage: A 10MΩ, 1/4W resistor used in a 500V DC measurement probe might theoretically only dissipate 0.025W, well under its 1/4W thermal limit. However, standard 1/4W resistors have a maximum voltage rating of ~250V. Exceeding this causes internal micro-arcing and catastrophic failure, regardless of wattage. For high voltage, you must use specialized high-voltage resistors or series chains.
- Temperature Coefficient (TCR): A 4-band resistor with a ±5% gold band might drift wildly as it heats up. If you are building a precision RTD amplifier or a multimeter voltage divider, you need a 5-band or 6-band resistor that explicitly states a low TCR (e.g., ±25 ppm/°C).
- Parasitic Inductance: Standard wire-wound or spiral-cut film resistors act as tiny inductors at high frequencies. If you are building an RF snubber or a high-speed oscilloscope probe compensation network, the color chart won't warn you that your 1kΩ resistor is actually 1kΩ + 50nH. You must select specific "non-inductive" thick-film parts.
- Composition and Noise: Carbon composition resistors (often found in vintage audio gear) generate significant thermal "current noise" compared to metal film. The color bands for a 1970s carbon comp and a 2026 Vishay metal film will be identical, but swapping them in a guitar amplifier preamp stage will drastically alter the noise floor.
For comprehensive datasheets and specific thermal derating curves for modern components, always cross-reference the manufacturer's part number (such as the Vishay PR02 or Yageo CFR series) rather than relying solely on the painted bands. For more on standard component values, review the E-series preferred numbers guide.
