# Resistor colour code calculator

> Resistor colour code calculator for 4, 5 and 6-band resistors: colours to ohms and tolerance, or a value to its bands, snapped to E12, E24 or E96.

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The resistor colour code in IEC 60062 marks a value with coloured bands: two or three significant digits, a multiplier band that gives the power of ten, a tolerance band, and on 6-band parts a temperature-coefficient band. It works both ways here: pick the colours to get the resistance and its tolerance range, or type a resistance to get the bands.

The default, yellow violet red gold, reads 47 × 10² Ω = 4.7 kΩ ±5%, so a part measuring anywhere from 4,465 Ω to 4,935 Ω is in specification. Going from a value to colours, the value can first be snapped to the nearest IEC 60063 preferred value: 5 kΩ is not in E12, so it becomes 4.7 kΩ, yellow violet red.

Gold and silver never start a reading because they carry no digit. When bands are faded or look alike, confirm the value with a multimeter.

## 输入

- **Direction** (选项：Colours → value, Value → colours)
- **Number of bands** (选项：4 bands, 5 bands, 6 bands)
- **Band 1 (first digit)** (选项：Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White)
- **Band 2 (second digit)** (选项：Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White)
- **Band 3 (third digit)** (选项：Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White)
- **Multiplier band** (选项：Pink, Silver, Gold, Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White)
- **Tolerance band** (选项：Silver, Gold, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, No band)
- **Temperature coefficient band** (选项：Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey)
- **Resistance**: Accepts 4.7k or 2.2M
- **Resistance unit** (选项：mΩ, Ω, kΩ, MΩ)
- **Snap to series** (选项：Don't snap, E6, E12, E24, E48, E96, E192)
- **Tolerance** (选项：Silver, Gold, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, No band)
- **Temperature coefficient (6 bands)** (选项：Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey)

## 结果

- Resistance (Ω) — 主要结果
- Marked value
- Bands
- Tolerance
- Minimum within tolerance (Ω)
- Maximum within tolerance (Ω)
- Temperature coefficient (ppm/K)
- Smallest E-series containing the value

## 公式

$$
R = (d_1d_2[d_3]) \times 10^{m},\qquad R_{\min,\max} = R\,(1 \mp t)
$$

## 计算示例

### Yellow violet red gold

- Direction: Colours → value
- Number of bands: 4 bands
- Band 1 (first digit): Yellow
- Band 2 (second digit): Violet
- Multiplier band: Red
- Tolerance band: Gold
- **Resistance: 4,700 Ω**
- **Tolerance: 5%**
- **Minimum within tolerance: 4,465 Ω**
- **Maximum within tolerance: 4,935 Ω**
- **Marked value: 4.7 kΩ ±5%**
- 核验来源：IEC 60062 table: 4,7 × 10² Ω, gold = ±5%; 4700 × 0.95 / 1.05

### Brown black black brown brown (5 band)

- Direction: Colours → value
- Number of bands: 5 bands
- Band 1 (first digit): Brown
- Band 2 (second digit): Black
- Band 3 (third digit): Black
- Multiplier band: Brown
- Tolerance band: Brown
- **Resistance: 1,000 Ω**
- **Tolerance: 1%**
- **Minimum within tolerance: 990 Ω**
- 核验来源：IEC 60062 table: 100 × 10¹ Ω ±1%

### 5 kΩ snapped to E12

- Direction: Value → colours
- Number of bands: 4 bands
- Resistance: 5000
- Resistance unit: Ω
- Snap to series: E12
- Tolerance: Silver
- **Resistance: 4,700 Ω**
- **Bands: yellow, violet, red, silver**
- 核验来源：IEC 60063 E12 neighbours 4.7k and 5.6k: 5000/4700 = 1.064 < 5600/5000 = 1.12

### 6 band with 50 ppm/K

- Direction: Colours → value
- Number of bands: 6 bands
- Band 1 (first digit): Orange
- Band 2 (second digit): Orange
- Band 3 (third digit): Black
- Multiplier band: Brown
- Tolerance band: Brown
- Temperature coefficient band: Red
- **Resistance: 3,300 Ω**
- **Temperature coefficient: 50 ppm/K**
- **Smallest E-series containing the value: E6**
- 核验来源：IEC 60062 table: 330 × 10 Ω, brown ±1%, red TCR 50 ppm/K

### Gold multiplier: green blue gold gold

- Direction: Colours → value
- Number of bands: 4 bands
- Band 1 (first digit): Green
- Band 2 (second digit): Blue
- Multiplier band: Gold
- Tolerance band: Gold
- **Resistance: 5.6 Ω**
- **Maximum within tolerance: 5.88 Ω**
- 核验来源：IEC 60062 table: 56 × 10⁻¹ Ω ±5%

### No tolerance band means ±20%

- Direction: Colours → value
- Number of bands: 4 bands
- Band 1 (first digit): Brown
- Band 2 (second digit): Black
- Multiplier band: Orange
- Tolerance band: No band
- **Resistance: 10,000 Ω**
- **Minimum within tolerance: 8,000 Ω**
- **Maximum within tolerance: 12,000 Ω**
- 核验来源：IEC 60062: absent tolerance band = ±20%

## 常见问题

### How do you read a 4-band resistor colour code?

The first two bands are digits, the third is the multiplier and the fourth the tolerance. The digits run black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. Yellow, violet, red, gold therefore reads 47 × 10² = 4,700 Ω, with gold meaning ±5%.

### Which end of a resistor do you start reading from?

Start from the end away from the gold or silver band. Gold and silver have no digit value in IEC 60062; they only appear as a multiplier (×0.1 and ×0.01) or a tolerance (±5% and ±10%). The first band usually sits closer to its lead, and the tolerance band is often spaced apart from the others.

### What is the difference between 4, 5 and 6-band resistors?

A 4-band resistor carries two significant digits, enough for the E6 to E24 values used for ±5% to ±20% parts. A 5-band resistor carries three digits for the E48 to E192 values of ±2% and tighter parts: brown, black, black, red, brown is 100 × 10² Ω = 10 kΩ ±1%. A 6-band resistor adds a temperature-coefficient band.

### What does the temperature coefficient band mean?

It gives the resistance drift per kelvin in parts per million: brown 100 ppm/K, red 50, yellow 25, green 20, orange 15, blue 10, violet 5 and grey 1. A 3.3 kΩ resistor with a red band changes by 3,300 × 50 × 10⁻⁶ = 0.165 Ω per degree, about 4.1 Ω over a 25 °C rise.

### What if a resistor has only three bands?

A missing tolerance band means ±20%. Brown, black, orange with no fourth band is 10 kΩ, and any value from 8 kΩ to 12 kΩ is within specification. Such parts come from the E6 series (1.0, 1.5, 2.2, 3.3, 4.7, 6.8), whose steps of about 47% suit the wide tolerance.

### “Resistor colour code calculator”有多准确？

准确性取决于输入值和方法的假设。十进制运算使用50位有效数字，但估算、数值方法和源数据的精度可能较低；显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例：9。 例如，“Yellow violet red gold”根据IEC 60062 table: 4,7 × 10² Ω, gold = ±5%; 4700 × 0.95 / 1.05进行核验。

### 这种方法出自哪里？

IEC 60062:2016 — Marking codes for resistors and capacitors (colour code, tolerance and TCR bands); IEC 60063:2015 — Preferred number series for resistors and capacitors (E series); Wikipedia — Electronic color code (summary of the IEC 60062 table).

## 来源

- IEC 60062:2016 — Marking codes for resistors and capacitors (colour code, tolerance and TCR bands)
- IEC 60063:2015 — Preferred number series for resistors and capacitors (E series)
- [Wikipedia — Electronic color code (summary of the IEC 60062 table)](https://en.wikipedia.org/wiki/Electronic_color_code)