Resistor Color Code Calculator
Read a resistor’s value from its color bands. Works for 4-band, 5-band and 6-band resistors, with tolerance, the resistance range and the temperature coefficient.
Results
| Item | Value |
|---|
Quick Answer
Read the digit bands, then multiply by the multiplier band. Yellow (4), violet (7), red (×100), gold (±5%) is 47 × 100 = 4,700 Ω, or 4.7 kΩ ±5%. Five-band resistors have three digit bands, and six-band ones add a temperature coefficient band.
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Table of Contents
- Resistor Color Code Calculator
- Quick Answer
- Related Calculators
- How This Resistor Color Code Calculator Works
- How to Use the Resistor Color Code Calculator
- Core Formulas
- Key Terms
- Worked Example
- Real-Life Examples
- 4-Band vs 5-Band Resistors
- Color Code Table
- Common Mistakes to Avoid
- Frequently Asked Questions
- References & Sources
How This Resistor Color Code Calculator Works
Choose how many bands your resistor has, then pick the color of each band. The calculator joins the digit bands into a number, multiplies it by the multiplier band, and shows the resistance in ohms, kilohms or megohms, with the tolerance range. For 6-band resistors it also shows the temperature coefficient.
Quick explanation: each color stands for a number from 0 to 9.
- 4 bands: 2 digits, multiplier, tolerance.
- 5 bands: 3 digits, multiplier, tolerance.
- 6 bands: 5 bands plus temperature coefficient.
How to Use the Resistor Color Code Calculator
- Count the bands and choose 4, 5 or 6.
- Hold the resistor so the tolerance band (often gold or silver) is on the right.
- Pick the colors from left to right.
- Press Calculate.
- Read the resistance, tolerance and range.
Core Formulas
- Resistance: digits × 10^multiplier
- Lowest value: resistance × (1 − tolerance)
- Highest value: resistance × (1 + tolerance)
Black = 0, brown = 1, red = 2, orange = 3, yellow = 4, green = 5, blue = 6, violet = 7, grey = 8, white = 9.
Key Terms
- Resistor: a part that resists the flow of electric current.
- Ohm (Ω): the unit of resistance.
- Tolerance: how far the real value may be from the marked value.
- Multiplier: the power of ten applied to the digits.
- TCR: temperature coefficient of resistance, in parts per million per kelvin.
Worked Example
A 5-band resistor reads brown, black, black, red, brown.
- Digits: 1, 0, 0 = 100
- Multiplier: red = ×100, so 100 × 100 = 10,000 Ω = 10 kΩ
- Tolerance: brown = ±1%, so 9.9 kΩ to 10.1 kΩ
Real-Life Examples
- A common LED resistor: red, red, brown, gold is 220 Ω ±5%.
- A pull-up resistor: brown, black, orange, gold is 10 kΩ ±5%.
- A precision part: brown, black, black, brown, brown is 1 kΩ ±1%.
- Sorting a parts bin: quickly check unmarked resistors before use.
4-Band vs 5-Band Resistors
- 4-band: two significant digits, common on ±5% and ±10% resistors.
- 5-band: three significant digits, common on precision ±1% resistors.
- 6-band: adds how much the value changes with temperature.
Color Code Table
Source: IEC 60062, as listed on Wikipedia.
| Color | Digit | Multiplier | Tolerance | TCR (ppm/K) |
|---|---|---|---|---|
| Black | 0 | ×10^0 | – | 250 |
| Brown | 1 | ×10^1 | ±1% | 100 |
| Red | 2 | ×10^2 | ±2% | 50 |
| Orange | 3 | ×10^3 | ±0.05% | 15 |
| Yellow | 4 | ×10^4 | ±0.02% | 25 |
| Green | 5 | ×10^5 | ±0.5% | 20 |
| Blue | 6 | ×10^6 | ±0.25% | 10 |
| Violet | 7 | ×10^7 | ±0.1% | 5 |
| Grey | 8 | ×10^8 | ±0.01% | 1 |
| White | 9 | ×10^9 | – | – |
| Gold | – | ×0.1 | ±5% | – |
| Silver | – | ×0.01 | ±10% | – |
| Pink | – | ×0.001 | – | – |
| None | – | – | ±20% | – |
Common Mistakes to Avoid
- Reading from the wrong end. Start from the end farther from the tolerance band.
- Mixing up brown, red and orange. Check under bright light.
- Forgetting gold and silver multipliers. They divide by 10 and 100.
- Ignoring tolerance. The real value can be anywhere in the range.
- Counting the bands wrong. A gap usually separates the tolerance band.
Frequently Asked Questions
Read the digit bands, then multiply by the multiplier band, and check the tolerance band.
1, 0, ×100 = 1,000 Ω, or 1 kΩ.
2, 2, ×10 = 220 Ω.
As a tolerance band, ±5%. As a multiplier band, ×0.1.
As a tolerance band, ±10%. As a multiplier band, ×0.01.
Start from the end opposite the tolerance band, which is usually gold, silver or set apart by a gap.
A missing band means ±20%.
The temperature coefficient, how much the resistance changes with temperature.
Bands can be read from any side of a small, round part, where printed numbers would be hard to see.
Measure it with a multimeter set to ohms, with the resistor out of the circuit.
Kilohms, or thousands of ohms. 4.7 kΩ = 4,700 Ω.
±5% (gold) and ±1% (brown) are very common.
Many people use a memory phrase for black, brown, red, orange, yellow, green, blue, violet, grey and white, or think of the rainbow order from red to violet between brown and grey.
Resistors are made in standard value series, called E series, such as E12 and E24. The values are spaced so that, with tolerance, they cover the whole range without big gaps.
They usually have a single black band. They act like a wire link on a circuit board.
No. Small surface mount resistors use printed number codes instead of color bands.
References & Sources
| Source | Used For | Link |
|---|---|---|
| Wikipedia, Electronic color code | The IEC 60062 colors, multipliers, tolerances and TCR. | https://en.wikipedia.org/wiki/Electronic_color_code |
| Wikipedia, Resistor | How resistors work and their markings. | https://en.wikipedia.org/wiki/Resistor |