Resistor Color Code Calculator
Identify resistor values from color bands or find the correct color code for any resistance value. Supports 4-band, 5-band, and 6-band resistors with a live visual diagram.
How to Read Resistor Color Codes
Every axial through-hole resistor uses colored bands to indicate its resistance value, tolerance, and sometimes temperature coefficient. Reading these bands is a fundamental skill for anyone working with electronics.
Step 1: Orient the Resistor
Hold the resistor so the tolerance band (usually Gold or Silver) is on the right side. The tolerance band is often spaced slightly further from the other bands. If there is no tolerance band, the resistor has +/-20% tolerance.
Step 2: Read the Digit Bands
Read the first two bands (4-band) or first three bands (5-band) from left to right. Each color represents a digit from 0-9: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9.
Step 3: Apply the Multiplier
The next band is the multiplier, which tells you how many zeros to add (or the power of 10 to multiply by). For example, Red = x100, Orange = x1,000, Yellow = x10,000. Gold = x0.1 and Silver = x0.01 are used for sub-10-ohm values.
Step 4: Note the Tolerance
The last band indicates how close the actual resistance is to the stated value. Gold = +/-5%, Silver = +/-10%, Brown = +/-1%. For a 1 kOhm resistor with Gold tolerance, the actual value is between 950 and 1,050 ohms.
Worked Example: 4-Band Resistor
Bands: Brown - Black - Red - Gold
- 1st Band (Brown): Digit = 1
- 2nd Band (Black): Digit = 0
- 3rd Band (Red): Multiplier = x100
- 4th Band (Gold): Tolerance = +/-5%
Result: 10 x 100 = 1,000 ohms = 1 kOhm +/-5% (range: 950 to 1,050 ohms)
Resistor Color Code Chart
Complete reference table showing the digit value, multiplier, tolerance, and temperature coefficient for each resistor color band.
| Color | Band | Digit | Multiplier | Tolerance | Temp Coeff |
|---|---|---|---|---|---|
| Black | 0 | x1 | — | — | |
| Brown | 1 | x10 | ±1% | 100 ppm/K | |
| Red | 2 | x100 | ±2% | 50 ppm/K | |
| Orange | 3 | x1k | ±0.05% | 15 ppm/K | |
| Yellow | 4 | x10k | ±0.02% | 25 ppm/K | |
| Green | 5 | x100k | ±0.5% | — | |
| Blue | 6 | x1M | ±0.25% | 10 ppm/K | |
| Violet | 7 | x10M | ±0.1% | 5 ppm/K | |
| Grey | 8 | x100M | ±0.01% | 1 ppm/K | |
| White | 9 | x1G | — | — | |
| Gold | — | x0.1 | ±5% | — | |
| Silver | — | x0.01 | ±10% | — |
4-Band vs 5-Band vs 6-Band Resistors
Resistors come in three common band configurations. The number of bands determines the precision and amount of information encoded on the component.
4-Band Resistors
- Bands: 2 digits + multiplier + tolerance
- Precision: 2 significant figures
- Typical Tolerance: +/-5% (Gold) or +/-10% (Silver)
- Use: General-purpose circuits, hobby projects, prototyping
5-Band Resistors
- Bands: 3 digits + multiplier + tolerance
- Precision: 3 significant figures
- Typical Tolerance: +/-1% (Brown) or +/-0.5% (Green)
- Use: Precision circuits, measurement equipment, professional designs
6-Band Resistors
- Bands: 3 digits + multiplier + tolerance + temp coefficient
- Precision: 3 significant figures + thermal stability
- Typical Tolerance: +/-1% or better
- Use: Temperature-sensitive circuits, instrumentation, aerospace
How This Calculator Works
This calculator operates in two modes to cover every use case:
Color to Value Mode
Select the color for each band position using the clickable swatches. The calculator instantly computes the resistance value, tolerance percentage, and min/max range. The live SVG diagram updates as you select colors so you can visually verify your reading.
Value to Color Mode
Enter any resistance value using flexible formats like "4.7k", "4K7", "470", or "1M". Select your desired tolerance, and the calculator shows the correct color band sequence. This is useful when you need to pick the right resistor from a parts bin or verify a schematic value.
Formulas
4-Band: Resistance = (D1 x 10 + D2) x Multiplier
5-Band / 6-Band: Resistance = (D1 x 100 + D2 x 10 + D3) x Multiplier
Where D1, D2, D3 are the digit values (0-9) and Multiplier is the power-of-10 factor from the multiplier band.
Frequently Asked Questions
How do I read a 4-band resistor color code?
A 4-band resistor has two digit bands, one multiplier band, and one tolerance band. Read left to right: the first two bands give a two-digit number, the third band is the multiplier (number of zeros), and the fourth band indicates tolerance. For example, Brown-Black-Red-Gold = 10 x 100 = 1,000 ohms (1 kOhm) with +/-5% tolerance.
What is the difference between 4-band and 5-band resistors?
A 5-band resistor has three digit bands instead of two, giving an extra digit of precision. The first three bands are digits, the fourth is the multiplier, and the fifth is tolerance. 5-band resistors are used in precision circuits where tighter tolerance values (1% or 0.5%) are needed.
What does the 6th band on a resistor mean?
The 6th band on a resistor indicates the temperature coefficient, measured in parts per million per Kelvin (ppm/K). This tells you how much the resistance changes with temperature. Common values include Brown = 100 ppm/K, Red = 50 ppm/K, and Blue = 10 ppm/K. Six-band resistors are used in high-precision, temperature-sensitive applications.
Which direction do I read resistor color bands?
Read from left to right, with the tolerance band on the right side. The tolerance band (usually Gold or Silver) is often spaced slightly further from the other bands. If both ends look similar, the first band is typically the one closest to the end of the resistor body. Gold and Silver can only be tolerance or multiplier bands, never digit bands, so they help identify the reading direction.
What does a Gold band mean on a resistor?
Gold has two possible meanings depending on its position. As a multiplier band (3rd or 4th band), Gold means multiply by 0.1, so it is used for resistor values below 10 ohms (e.g., 4.7 ohm). As a tolerance band (last band), Gold means +/-5% tolerance. Gold is one of the most common tolerance bands found on general-purpose resistors.
What does a Silver band mean on a resistor?
Like Gold, Silver has two roles. As a multiplier, Silver means multiply by 0.01, used for sub-1-ohm resistors. As a tolerance band (last band), Silver means +/-10% tolerance. Silver-tolerance resistors are less precise than Gold-tolerance ones and are used in non-critical circuits.
What does it mean when a resistor has no tolerance band?
A resistor with no tolerance band (only 3 colored bands visible) has a default tolerance of +/-20%. These are the least precise resistors available and are uncommon in modern electronics. Most resistors today have at least a Gold (+/-5%) tolerance band.
How do I calculate resistance from color bands?
For a 4-band resistor: combine the first two digit bands into a two-digit number, then multiply by the third band (multiplier). For example, Red (2) - Violet (7) - Orange (x1,000) = 27 x 1,000 = 27,000 ohms = 27 kOhm. For a 5-band resistor, combine three digits before applying the multiplier.
What are the most common resistor values?
Resistors follow the E-series of preferred numbers. The most common series is E24 (5% tolerance), which includes values like 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, and their multiples. Popular values include 100 ohm, 220 ohm, 470 ohm, 1 kOhm, 4.7 kOhm, 10 kOhm, 47 kOhm, and 100 kOhm.
Can I use this calculator for SMD resistors?
This calculator is designed for through-hole axial resistors with color bands. SMD (surface-mount) resistors use a numeric code printed on the component instead of color bands. For 3-digit SMD codes, the first two digits are significant figures and the third is the multiplier. For example, SMD code 472 = 47 x 100 = 4,700 ohms.
Resistor Color Codes in Electrical Work
While resistor color codes are primarily used in electronics, electricians encounter them when working with control circuits, HVAC systems, fire alarm panels, and industrial automation. Understanding Ohm's law is fundamental to both fields. Use our Ohm's Law Calculator to calculate voltage, current, and power relationships.
For wire sizing and voltage drop calculations in full-scale electrical installations, check out our Wire Sizing Calculator and Voltage Drop Calculator.
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