Resistor Color Code Calculator

Decode 3, 4, 5, and 6-band resistors to ohms, tolerance, and temperature coefficient — or convert any resistance value back to its EIA color bands.

Number of bands

How Resistor Color Codes Work

The resistor color code is an EIA-standardized system for marking axial lead resistors with colored bands that encode resistance, tolerance, and (optionally) temperature coefficient. Each color maps to a digit 0–9, a multiplier, a tolerance percentage, or a temperature coefficient value.

Reading order: bands are read from the end closest to the lead (the side with bands grouped together) toward the center of the body. The last band (usually separated by a larger gap) indicates tolerance — and on 6-band resistors, the very last band indicates the temperature coefficient.

Color Code Reference Table

Color Digit Multiplier Tolerance Temp. Coeff. (ppm/°C)

Reading a 4-Band Resistor

A 4-band resistor uses the first two bands for significant digits, the third as the multiplier (power of ten), and the fourth for tolerance. For example, Yellow-Violet-Red-Gold = 4, 7, ×100, ±5% = 4700 Ω ±5% (4.7 kΩ).

5- and 6-band resistors add a third significant digit, giving finer resolution for precision resistors. The 6th band denotes the temperature coefficient (TCR), important in precision and stability-critical circuits like oscillators and measurement bridges.

FAQ

Which side of the resistor do I read from?
Read from the side where the bands are grouped closest to the end of the body. The tolerance band is usually separated from the value bands by a slightly larger gap and is often a metallic color (gold or silver). When in doubt, the gold/silver/precision band is the tolerance and belongs on the right.
What's the difference between 3, 4, 5, and 6-band resistors?
A 3-band resistor has two significant digits + multiplier and an implied ±20% tolerance. 4-band adds an explicit tolerance band (the most common type). 5-band adds a third significant digit for precision values (typically ±1% or better). 6-band adds a temperature coefficient band for high-stability applications.
How do I write resistance values like 4.7 kΩ or 0.5 Ω as text?
Use the convention: R for ohms (4R7 = 4.7 Ω), k or K for kilohms (4k7 = 4.7 kΩ), and M for megohms (1M = 1 MΩ). The letter replaces the decimal point, which prevents misreading when decimal marks are smudged on small components.
Why is gold/silver used as a multiplier that makes the value smaller?
Gold (×0.1) and silver (×0.01) are used to encode resistances below 10 Ω, since the standard digit multipliers (×1, ×10, ×100, …) can't reach sub-10 Ω values. For example, Red-Red-Gold = 2, 2, ×0.1 = 2.2 Ω.
What does the temperature coefficient (TCR) band mean?
The TCR, in parts per million per degree Celsius (ppm/°C), describes how much the resistance drifts with temperature. Lower is better for precision circuits. For example, a brown 6th band (100 ppm/°C) means a 100 Ω resistor changes by 100 × 100 × 10⁻⁶ = 0.01 Ω per °C of temperature change.
How do I read a 4-band resistor color code?
The first two bands are significant digits, the third is the multiplier (power of 10), and the fourth is tolerance. Example: Yellow(4)-Violet(7)-Orange(×1,000)-Gold(±5%) = 47,000 Ω = 47 kΩ at ±5%. Use the mnemonic: Black(0), Brown(1), Red(2), Orange(3), Yellow(4), Green(5), Blue(6), Violet(7), Gray(8), White(9).
What's the difference between 4-band and 5-band resistors?
4-band resistors have two significant digits (suitable for values in the E12/E24 series with ±5% or ±10% tolerance). 5-band resistors have three significant digits for finer resolution (E48/E96 series with ±1% or ±2% tolerance). Precision circuits use 5-band; general-purpose circuits typically use 4-band. The extra digit allows values like 4.72 kΩ that aren't available in 4-band.
How do I know which side is the first band?
Most resistors have the tolerance band (gold, silver, or a wider-spaced band) on the right. Read from the end where the bands are closest together. If both ends look similar, the first band is never gold or silver. When truly ambiguous, measure with a multimeter. Some manufacturers use a wider gap between the value bands and tolerance band as a visual cue.
What do the tolerance colors mean?
Brown = ±1%, Red = ±2%, Gold = ±5%, Silver = ±10%, No band = ±20%. Gold and silver are the most common in general-purpose resistors. Precision resistors (±0.1% to ±0.5%) use other color codes (violet, blue, green) but are typically marked with printed numbers instead of color bands due to the tighter specification.

How to Use the Resistor Color Code Calculator

  1. Select the number of bands — choose 3, 4, 5, or 6-band resistor based on your component.
  2. Set each band's color by clicking on the color picker for each position — the resistor image updates in real time.
  3. Read the resistance value in ohms (Ω), kilo-ohms (kΩ), or mega-ohms (MΩ) along with tolerance and temperature coefficient (for 6-band).
  4. Or enter a resistance value to convert it back to color bands for identification.
  5. Reference the EIA color code chart for a complete color-to-value mapping.

Understanding Resistor Color Codes

The resistor color code system, standardized by EIA (Electronic Industries Alliance), uses colored bands to mark resistance values on small cylindrical components where printed numbers would be illegible. Each color maps to a digit (0–9), a multiplier (power of 10), or a tolerance percentage. The mnemonic "Bad Boys Race Our Young Girls But Violet Generally Wins" encodes the digit sequence: Black(0), Brown(1), Red(2), Orange(3), Yellow(4), Green(5), Blue(6), Violet(7), Gray(8), White(9).

4-band resistors are the most common type. The first two bands are significant digits, the third is the multiplier, and the fourth is tolerance. For example: Yellow-Violet-Red-Gold = 4, 7, ×100, ±5% = 4,700 Ω (4.7 kΩ) at ±5%. 5-band resistors add a third significant digit for precision: the first three bands are digits, the fourth is multiplier, and the fifth is tolerance. Red-Red-Black-Brown-Brown = 2, 2, 0, ×10, ±1% = 2,200 Ω (2.2 kΩ). 3-band resistors omit the tolerance band (assumed ±20%), and 6-band resistors add a temperature coefficient band (typically 50–100 ppm/°C) for high-precision applications.

Identifying which band is "first" can be tricky. On most resistors, the tolerance band (gold, silver, or a wider gap) is on the right, and you read left-to-right from the side closest to the bands. Some resistors have a wider gap between the value bands and the tolerance band as a visual cue. When in doubt, the first band is never gold or silver (those are only multipliers or tolerance colors). The most common tolerance bands are Gold (±5%) and Brown (±1%) — Silver (±10%) is rare in modern components, and no tolerance band means ±20%.

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