How to use the resistor color code calculator
- Select whether your component has 4, 5 or 6 bands.
- Match each color stripe on the physical part to the corresponding dropdown, starting from the end closest to the edge.
- Read the decoded resistance value, tolerance range and temperature coefficient below.
- Use the result to verify replacement parts or check circuit designs.
How the resistor color code works
The resistor color code assigns a digit from 0 to 9 to each color. In a 4-band resistor, the first two bands form a two-digit number, the third band is a power-of-ten multiplier, and the fourth band indicates tolerance. For example, brown-black-red-gold means 1 and 0 (forming 10), multiplied by 102 (100), giving 1,000 ohms or 1 kΩ, with a gold tolerance of ±5%.
A 5-band resistor adds a third significant digit before the multiplier, allowing more precise values. A 6-band resistor adds a sixth stripe for the temperature coefficient, measured in parts per million per Kelvin (ppm/K). This resistor calculator handles all three formats automatically based on your selection.
Color to digit reference table
Every standard resistor uses the same color mapping. Keep this table handy when reading bands under poor lighting or when the paint is faded.
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | |
| Yellow | 4 | ×10,000 | |
| Green | 5 | ×100,000 | ±0.5% |
| Blue | 6 | ×1,000,000 | ±0.25% |
| Violet | 7 | ×10,000,000 | ±0.1% |
| Grey | 8 | ×100,000,000 | ±0.05% |
| White | 9 | ×1,000,000,000 | |
| Gold | ×0.1 | ±5% | |
| Silver | ×0.01 | ±10% |
Reading orientation and common mistakes
The most frequent error when using a resistor calculator is reading the bands backwards. The tolerance band (usually gold or silver) is spaced slightly farther from the others or sits over the rounded shoulder of the component. Always start reading from the opposite end.
Faded colors cause another problem. Red can look orange, and green can appear blue under warm workshop lighting. If you are unsure, measure the component with a multimeter and compare it against the decoded value. Also remember that zero-ohm resistors exist: they have a single black band and serve as wire links on printed circuit boards.
Understanding tolerance and temperature coefficient
Tolerance defines the manufacturing spread. A 10 kΩ resistor with ±5% tolerance may actually measure anywhere between 9,500 and 10,500 ohms. Precision circuits often require 1% or 0.1% tolerance parts, which use 5 or 6 bands to encode the extra significant digit.
The temperature coefficient (TCR) matters in environments where heat fluctuates. A TCR of 100 ppm/K means that for every degree Celsius change in temperature, the resistance shifts by 100 parts per million. On a 10,000 ohm resistor, a 50-degree rise changes the value by about 50 ohms. Six-band resistors include this specification as their final stripe.
When to use 4-band versus 5-band resistors
Four-band resistors cover general-purpose applications like pull-up networks, LED current limiting and basic voltage dividers. They offer two significant digits, which is sufficient when exact precision is not critical.
Five-band and six-band resistors appear in measurement equipment, audio circuits and feedback loops where tighter accuracy is required. The third digit allows values such as 4.75 kΩ instead of rounding to 4.7 kΩ. When replacing a component, always match both the resistance value and the tolerance rating to avoid altering circuit behavior.
Worked examples
Each result below was produced by the same code the tool runs, so you can check your own numbers against them.
| Example | Input | Result |
|---|---|---|
| 4-band 10k ohm 5% | Number of bands: 4; Band 1 (1st digit): brown; Band 2 (2nd digit): black; Band 3 (3rd digit, 5/6-band only): black; Multiplier band: orange; Tolerance band: gold; Temp. coefficient (6-band only): brown | Resistance: 10 kΩ; Tolerance: ±5% |
| 5-band 4.7k ohm 1% | Number of bands: 5; Band 1 (1st digit): yellow; Band 2 (2nd digit): violet; Band 3 (3rd digit, 5/6-band only): black; Multiplier band: brown; Tolerance band: brown; Temp. coefficient (6-band only): brown | Resistance: 4.7 kΩ; Tolerance: ±1% |
| 6-band precision 100 ohm | Number of bands: 6; Band 1 (1st digit): brown; Band 2 (2nd digit): black; Band 3 (3rd digit, 5/6-band only): black; Multiplier band: black; Tolerance band: brown; Temp. coefficient (6-band only): red | Resistance: 100 Ω; Tolerance: ±1%; Temp. coefficient: 50 ppm/K |
| 4-band 220 ohm 5% | Number of bands: 4; Band 1 (1st digit): red; Band 2 (2nd digit): red; Band 3 (3rd digit, 5/6-band only): black; Multiplier band: brown; Tolerance band: gold; Temp. coefficient (6-band only): brown | Resistance: 220 Ω; Tolerance: ±5% |
FAQ
Which end of the resistor do I start reading from?
Start from the end closest to a color band. The tolerance band, typically gold or silver, is usually spaced wider or sits near the opposite end. Read away from the tolerance band toward it.
What does a resistor with no bands mean?
A completely unmarked axial component might be a wire link or a damaged part. A single black band indicates a zero-ohm jumper used as a bridge on circuit boards.
Can I replace a 5-band resistor with a 4-band one?
Only if the resistance value matches and the wider tolerance of the 4-band part is acceptable for your circuit. Precision analog stages usually require the exact tolerance the original design specified.
Why does my multimeter show a different value than the color code?
The color code gives the nominal value. The actual resistance falls within the tolerance range. Temperature, lead resistance and meter accuracy also contribute small differences.
Are there resistors with more than 6 bands?
Standard through-hole resistors use up to 6 bands. Some military-specification or custom parts add reliability or failure-rate bands, but these are rare in consumer electronics.
Does this resistor calculator work for surface-mount parts?
No. Surface-mount resistors use printed numeric codes like "103" (meaning 10 x 10^3 = 10 kΩ) rather than color bands. This tool is designed specifically for through-hole axial resistors.