Resistor Color Code Guide

Introduction

Reading resistor color codes is an essential skill for anyone working with electronics, from hobbyists building circuits to professional engineers designing complex systems. Resistor color codes provide a compact, standardized method to identify resistance values and tolerances without requiring printed text on small components.

The color code system, standardized by IEC 60062, uses colored bands to represent digits, multipliers, and tolerance values, enabling quick identification of resistor values even when components are mounted on circuit boards.

Mastering the resistor color code is a rite of passage for every electronics enthusiast. Whether you're decoding a vintage amplifier or assembling a modern PCB, these colorful bands hold the key to your circuit's behavior.

In this complete guide, you'll learn to:

• Decode 4, 5, and 6-band resistors with confidence.
• Interpret tolerance bands (Gold, Silver, Brown) correctly.
• Verify values against standard E-series (E12, E24, E96).
• Avoid common pitfalls like reading from the wrong end.

Quick Answer: How to Read Resistor Color Codes

Resistor color codes use colored bands to indicate resistance value and tolerance.

Band Configuration

Color Chart

Multiplier Guide

Tolerance Guide

Reference Table

Key Standards

Worked Examples

Tolerance Guide:

Key Points:

• Most Common: Gold ($\pm 5\%$) and Silver ($\pm 10\%$) are the most frequently used tolerances
• Precision Resistors: Brown ($\pm 1\%$), Red ($\pm 2\%$), and Green ($\pm 0.5\%$) are used in precision circuits
• Tolerance Band Location: The tolerance band is typically narrower and positioned closer to one end of the resistor
• Reading Direction: Always read from the end opposite the tolerance band per IEC 60062 standard

E-Series Standard Values:

Resistors are manufactured in standardized values according to IEC 60063 to ensure manufacturing consistency and prevent tolerance overlap. The E-series defines preferred number sequences that guarantee adjacent values don't overlap even at maximum tolerance.

E12 Series Values ($\pm 10\%$ tolerance): 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82

E24 Series Values ($\pm 5\%$ tolerance): Includes all E12 values plus: 11, 13, 16, 20, 24, 30, 36, 43, 51, 62, 75, 91

E96 Series Values ($\pm 1\%$ tolerance): 96 precision values per decade (e.g., 100, 102, 105, 107, 110, 113, 115, 118, 121, 124, 127, 130...)

Key Principle: E-series values are calculated so that the maximum value of one resistor (value + tolerance) doesn't overlap with the minimum value of the next (value - tolerance). This ensures any measured resistance can be uniquely identified with its standard value.

Reading direction: Always read from the end OPPOSITE the tolerance band (gold/silver) per IEC 60062 standard

What is the Resistor Color Code?

The resistor color code is a standardized color-marking system used to indicate the resistance value, tolerance, and sometimes temperature coefficient of resistors. Developed in the 1920s and standardized by IEC 60062, this system allows manufacturers to print component values on tiny resistors where numerical printing would be impractical.

Each color band on a resistor represents a specific digit or multiplier, enabling engineers and technicians to quickly identify resistance values without measuring equipment. Understanding this code is fundamental to electronics work, from hobbyist projects to professional circuit design.

Understanding Band Systems

Resistors use different band systems depending on their precision and manufacturing requirements. The number of bands indicates the resistor's precision level and the information it provides.

4-Band Resistor ($\pm 5\%$ to $\pm 10\%$ Tolerance)

The most common type, typically used for general-purpose applications where high precision isn't critical.

Band Configuration:

Example: Brown-Black-Red-Gold = $10 \times 100 = 1,000 \Omega \pm 5\%$ (1 kΩ)

Reading Direction: The tolerance band (gold or silver) is typically narrower and positioned closer to one end. Always read from the end opposite the tolerance band per IEC 60062 standard.

Common Applications:

• General-purpose circuits
• Hobbyist projects
• Non-critical timing circuits
• Power supply circuits

5-Band Resistor ($\pm 0.5\%$ to $\pm 2\%$ Tolerance)

Used for precision applications requiring tighter tolerances. Provides three significant digits instead of two.

Band Configuration:

Example: Brown-Black-Red-Brown-Red = $102 \times 10 = 1,020 \Omega \pm 2\%$

Advantages:

• Three significant digits provide 1,000 possible values per decade (vs. 100 for 4-band)
• Enables more precise resistance specifications
• Better suited for precision analog circuits

Common Applications:

• Precision measurement equipment
• Analog signal processing
• Feedback circuits requiring tight tolerances
• Audio equipment

6-Band Resistor ($\pm 0.1\%$ to $\pm 1\%$ Tolerance)

High-precision resistors with temperature coefficient information. Used in applications where resistance stability over temperature is critical.

Band Configuration:

Example: Brown-Black-Red-Brown-Brown-Red = $102 \times 10 = 1,020 \Omega \pm 1\%$, 50 ppm/°C

Temperature Coefficient (Band 6):

• Indicates how much resistance changes per degree Celsius
• Lower values (e.g., 5-25 ppm/°C) indicate better temperature stability
• Critical for precision circuits operating over wide temperature ranges

Common Applications:

• Precision measurement instruments
• Temperature-sensitive analog circuits
• Medical equipment
• Aerospace and military applications
• High-accuracy voltage references

Band System Comparison

Color Code Chart

Standard Color Values

Complete reference table for resistor color code values per IEC 60062 standard:

Notes:

• Digit Column: Used for bands 1, 2, and 3 (in 5-band and 6-band resistors)
• Multiplier Column: Used for band 3 (4-band) or band 4 (5-band and 6-band resistors)
• Tolerance Column: Used for the tolerance band (band 4, 5, or 6 depending on resistor type)
• Temp Coeff Column: Used only in 6-band resistors (band 6) to indicate temperature coefficient
• Gold and Silver: Never used as digit values; only as multipliers (for values < 1Ω) or tolerance bands

E-Series Standard Values

To ensure manufacturing consistency and inventory management, resistors are manufactured in standardized values according to the E-series defined in IEC 60063. The E-series uses logarithmic spacing to ensure that tolerance bands of adjacent values don't overlap, making manufacturing and component selection more consistent.

E-Series Overview

E12 Series ($\pm 10\%$ Tolerance)

12 values per decade with approximately 21% spacing between values:

Values: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82

Example Values Across Decades:

• $10 \Omega, 12 \Omega, 15 \Omega, 18 \Omega, 22 \Omega, 27 \Omega, 33 \Omega, 39 \Omega, 47 \Omega, 56 \Omega, 68 \Omega, 82 \Omega$
• $100 \Omega, 120 \Omega, 150 \Omega, 180 \Omega, 220 \Omega, 270 \Omega, 330 \Omega, 390 \Omega, 470 \Omega, 560 \Omega, 680 \Omega, 820 \Omega$
• $1 \text{k}\Omega, 1.2 \text{k}\Omega, 1.5 \text{k}\Omega, 1.8 \text{k}\Omega, 2.2 \text{k}\Omega, 2.7 \text{k}\Omega, 3.3 \text{k}\Omega, 3.9 \text{k}\Omega, 4.7 \text{k}\Omega, 5.6 \text{k}\Omega, 6.8 \text{k}\Omega, 8.2 \text{k}\Omega$

Use Case: Most common for general-purpose circuits where exact values aren't critical.

E24 Series ($\pm 5\%$ Tolerance)

24 values per decade with approximately 10% spacing between values. Includes all E12 values plus intermediate values.

Values: 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91

Additional Values Beyond E12: 11, 13, 16, 20, 24, 30, 36, 43, 51, 62, 75, 91

Use Case: Standard precision resistors, most common for 5-band resistors.

E48 Series ($\pm 2\%$ Tolerance)

48 values per decade with approximately 5% spacing between values.

Sample Values: 100, 105, 110, 115, 121, 127, 133, 140, 147, 154, 162, 169, 178, 187, 196, 205, 215, 226, 237, 249, 261, 274, 287, 301, 316, 332, 348, 365, 383, 402, 422, 442, 464, 487, 511, 536, 562, 590, 619, 649, 681, 715, 750, 787, 825, 866, 909, 953

Use Case: Precision applications requiring tighter tolerances than E24.

E96 Series ($\pm 1\%$ Tolerance)

96 values per decade with approximately 2% spacing between values.

Sample Values: 100, 102, 105, 107, 110, 113, 115, 118, 121, 124, 127, 130, 133, 137, 140, 143, 147, 150, 154, 158, 162, 165, 169, 174, 178, 182, 187, 191, 196, 200, 205, 210, 215, 221, 226, 232, 237, 243, 249, 255, 261, 267, 274, 280, 287, 294, 301, 309, 316, 324, 332, 340, 348, 357, 365, 374, 383, 392, 402, 412, 422, 432, 442, 453, 464, 475, 487, 499, 511, 523, 536, 549, 562, 576, 590, 604, 619, 634, 649, 665, 681, 698, 715, 732, 750, 768, 787, 806, 825, 845, 866, 887, 909, 931, 953, 976

Use Case: High-precision resistors, commonly used in 5-band and 6-band precision resistors.

E192 Series ($\pm 0.5\%$ Tolerance)

192 values per decade with approximately 1% spacing between values.

Use Case: Ultra-high precision applications, measurement equipment, and critical analog circuits.

E-Series Mathematical Formula

The E-series values follow a logarithmic progression:

Where:

• $R_n$ = Resistance value at step $n$
• $R_1$ = First value in the decade (typically 10)
• $N$ = Series number (12, 24, 48, 96, or 192)
• $n$ = Step number (0 to $N-1$)

Example: For E24 series, the 5th value ($n=4$):

Why E-Series Exists

Tolerance Overlap Prevention: The logarithmic spacing ensures that the maximum value of one resistor (value + tolerance) doesn't overlap with the minimum value of the next (value - tolerance).

Example: For E12 series with $\pm 10\%$ tolerance:

• $10 \Omega \pm 10\% = 9 \Omega$ to $11 \Omega$
• $12 \Omega \pm 10\% = 10.8 \Omega$ to $13.2 \Omega$

The maximum of $10 \Omega$ (11 $\Omega$) is less than the minimum of $12 \Omega$ (10.8 $\Omega$), ensuring no overlap.

Benefits:

• Manufacturing consistency across different manufacturers
• Efficient inventory management
• Guaranteed unique identification of resistance values
• Standardized component selection in circuit design

Worked Example: 4-Band Resistor

Let's decode a resistor with these colors: Brown, Black, Red, Gold

Step 1: Identify the Tolerance Band

Gold band = $\pm 5\%$ tolerance → This is a 4-band resistor

The tolerance band (gold or silver) is typically narrower and positioned closer to one end. This helps identify the reading direction.

Step 2: Read from the Opposite End

Reading left to right: Brown, Black, Red, Gold

Always read from the end opposite the tolerance band per IEC 60062 standard.

Step 3: Decode Each Band

Step 4: Calculate Resistance

Resistance Calculation:

Combine the digits and apply the multiplier:

$R = (10 + 0) \times 100 = 10 \times 100 = 1,000\,\Omega = 1\,\text{k}\Omega$

Step 5: Determine Tolerance Range

With $\pm 5\%$ tolerance:

Minimum Resistance:

$R_{\text{min}} = 1,000 \times (1 - 0.05) = 1,000 \times 0.95 = 950\,\Omega$

Maximum Resistance:

$R_{\text{max}} = 1,000 \times (1 + 0.05) = 1,000 \times 1.05 = 1,050\,\Omega$

Result: $1\,\text{k}\Omega \pm 5\%$ (range: $950\,\Omega$ to $1,050\,\Omega$)

Verification

This resistor is part of the E24 series ($1\,\text{k}\Omega$ is a standard E24 value). Any measured resistance between $950\,\Omega$ and $1,050\,\Omega$ is within specification.

Worked Example: 5-Band Resistor

Let's decode a precision resistor: Brown, Black, Black, Brown, Brown

Step 1: Identify Band Count

Five bands with consistent spacing → 5-band precision resistor

5-band resistors are used for precision applications requiring tighter tolerances ($\pm 0.5\%$ to $\pm 2\%$).

Step 2: Decode Each Band

Step 3: Calculate Resistance

5-Band Resistance Calculation:

Combine the three digits and apply the multiplier:

$R = (100 + 0 + 0) \times 10 = 100 \times 10 = 1,000\,\Omega = 1\,\text{k}\Omega$

Step 4: Determine Precision Range

With $\pm 1\%$ tolerance:

Minimum Resistance:

$R_{\text{min}} = 1,000 \times (1 - 0.01) = 1,000 \times 0.99 = 990\,\Omega$

Maximum Resistance:

$R_{\text{max}} = 1,000 \times (1 + 0.01) = 1,000 \times 1.01 = 1,010\,\Omega$

Result: $1\,\text{k}\Omega \pm 1\%$ (range: $990\,\Omega$ to $1,010\,\Omega$)

Comparison: 4-Band vs 5-Band

Key Insight: The 5-band resistor provides 5× tighter tolerance ($\pm 10\,\Omega$ vs $\pm 50\,\Omega$), making it essential for precision analog circuits, measurement equipment, and audio applications.

Verification

This resistor is part of the E96 series ($1\,\text{k}\Omega$ is a standard E96 value). Any measured resistance between $990\,\Omega$ and $1,010\,\Omega$ is within specification.

Industry Standards (IEC 60062)

IEC 60062:2016 - Marking codes for resistors and capacitors

This international standard, published by the International Electrotechnical Commission, defines:

1. Color coding systems for through-hole resistors
2. Alphanumeric marking for surface-mount devices (SMD)
3. Standard preferred values (E-series)
4. Tolerance and degree coefficient markings

Key Requirements:

• Colors must be clearly distinguishable under normal lighting
• Bands must be evenly spaced (except tolerance band)
• Reading direction indicated by band spacing or band width
• Minimum band width: 1mm for resistors $>10$mm length

Related Standards

• IEC 60063: Preferred number series for resistor values
• EIA-96: Alternative SMD resistor marking arrangement
• MIL-PRF-55342: US military specification for resistors

Common Mistakes

Mistake 1: Reading from the Wrong End

Problem: Resistor reads as 1.2k Ω instead of 120 Ω

Solution: The tolerance band (gold, silver, or close-tolerance colors like brown, red) is usually narrower and positioned closer to one end. Always read from the opposite end.

Mistake 2: Confusing Brown and Red Under Poor Lighting

Problem: Misreading $1\,\text{k}\Omega$ (brown-black-red) as $2\,\text{k}\Omega$ (red-black-red)

Solution: Use proper lighting and a magnifying glass. Brown appears darker/more muted than red. When in doubt, measure with a multimeter.

Mistake 3: Ignoring Tolerance

Problem: Expecting exactly 1000 Ω but measuring 1040 Ω and assuming the resistor is defective

Solution: A $\pm 5\%$ tolerance means any value between $950\,\Omega$ and $1050\,\Omega$ is within specification. Only values outside this range indicate a faulty component.

Mistake 4: Assuming All Resistors Have 4 Bands

Problem: Treating a 5-band resistor as 4-band, getting completely wrong value

Solution: Count bands carefully before decoding. Modern precision resistors almost always use 5 or 6 bands.

Mistake 5: Not Checking E-Series Validity

Problem: Calculating a value like $650\Omega$ from color bands when $680\Omega$ is the nearest standard value

Solution: After decoding, verify the value matches a standard E-series value. Non-standard values indicate misreading.

Using Our Resistor Color Code Calculator

Our Resistor Color Code Calculator simplifies the decoding process:

Features:

• 4, 5, and 6-band support: Handles all common resistor types
• Interactive color selection: Visual color picker for each band
• Instant calculation: Real-time resistance, tolerance, and range display
• E-series validation: Indicates which standard series the resistor belongs to
• Heat level coefficient: Shows thermal stability for 6-band resistors
• Reverse lookup: Use the calculator’s reverse mode to enter a target resistance and see valid band combinations automatically

Why Use Our Calculator?

1. Speed: Decode resistors in seconds instead of consulting charts
2. Accuracy: Eliminates human error in color interpretation
3. Learning tool: See formulas and explanations alongside results
4. Mobile-friendly: Use on your phone while working with components
5. Free and unlimited: No registration or usage limits

Our calculations follow industry best practices and have been validated against real-world scenarios.

Conclusion

The resistor color code is an elegant solution to component marking that has stood the test of time for nearly a century. Mastering this system is essential for anyone working with electronics, from beginners learning circuit basics to professional engineers designing complex systems.

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4-band resistors provide 2 significant digits with ±5-10% tolerance for general-purpose applications, while 5-band resistors offer 3 significant digits with ±0.5-2% tolerance for precision circuits. 6-band resistors add temperature coefficient information for high-precision applications requiring thermal stability.

E-series values (E12, E24, E96) ensure manufacturing consistency and inventory management, and IEC 60062 is the international standard governing color codes. Always verify decoded values against E-series standards to ensure accuracy.

Key Takeaways

• Read resistor color codes from the end opposite the tolerance band—4-band resistors have 2 digits + multiplier + tolerance, 5-band have 3 digits + multiplier + tolerance
• Use the color-to-value memory aid "Big Brown Rabbits Often Yield Great Big Vegetable Gardens Weekly" for digits 0-9: Black(0), Brown(1), Red(2), Orange(3), Yellow(4), Green(5), Blue(6), Violet(7), Gray(8), White(9)
• Apply multiplier bands correctly—multiplier adds zeros or decimal point (Gold = ×0.1, Silver = ×0.01) to the significant digits
• Interpret tolerance bands—Gold = ±5% (most common), Brown = ±1% (precision), Green = ±0.5% (high precision); tolerance determines acceptable resistance range
• 4-band resistors provide 2 significant digits with ±5-10% tolerance for general-purpose applications—most common type for hobbyist and commercial circuits
• 5-band resistors offer 3 significant digits with ±0.5-2% tolerance for precision circuits—used when tighter specifications are required
• 6-band resistors add temperature coefficient (25-100 ppm/°C) for high-precision applications requiring thermal stability analysis
• Always verify decoded values against E-series standards (E12, E24, E96)—non-standard values indicate misreading; use multimeter to confirm

Further Learning

• LED Resistor Guide - Applying resistor knowledge in practical LED circuits
• Ohm's Law Guide - Understanding how resistance affects voltage and current
• Voltage Divider Guide - Using resistors in voltage divider circuits
• Power Calculator - Calculate power dissipation in resistors
• Resistor Color Code Calculator - Interactive decoder tool

References & Standards

This guide follows established engineering principles and standards. For detailed requirements, always consult the current adopted edition in your jurisdiction.

Primary Standards

IEC 60062:2016 Marking codes for resistors and capacitors. Defines the international standard for resistor color codes, including 4-band, 5-band, and 6-band configurations. Specifies color-to-value mapping (Black=0 through White=9), multiplier bands, tolerance color codes (Gold=±5%, Brown=±1%, etc.), and temperature coefficient coding for 6-band resistors. Ensures consistent component identification worldwide.

IEC 60063:2015 Preferred number series for resistors and capacitors. Defines E12 (±10% tolerance, 12 values per decade), E24 (±5% tolerance, 24 values per decade), E48, E96 (±1% tolerance, 96 values per decade), and E192 standard value series. Ensures manufacturing consistency, prevents tolerance overlap between adjacent values, and enables efficient inventory management.

Supporting Standards & Guidelines

IEC 60050 - International Electrotechnical Vocabulary International standards for electrical terminology and definitions, including resistor and component marking terms.

Further Reading

• Resistor Color Code Chart - Interactive color code reference and calculator

Note: Standards and codes are regularly updated. Always verify you're using the current adopted edition applicable to your project's location. Consult with local authorities having jurisdiction (AHJ) for specific requirements.

Disclaimer: This guide provides general technical information based on international electrical standards. Always verify calculations with applicable local electrical codes (NEC, IEC, BS 7671, etc.) and consult licensed electrical engineers or electricians for actual installations. Electrical work should only be performed by qualified professionals. Component ratings and specifications may vary by manufacturer.