Engineering Guide
How to Read Resistor Color Codes
Learn how to identify resistor values using the standard 4-band, 5-band and 6-band resistor color code system.
- Reading Time
- 10 min
- Difficulty
- Beginner
- Last Updated
- July 11, 2026
Introduction
Resistor color codes exist because many through-hole resistors are too small to print a full resistance value on the body. Instead of text such as 4.7 kΩ or 10 kΩ, manufacturers use colored bands that encode significant digits, multiplier, tolerance, and sometimes temperature coefficient.
Engineers should understand these bands because resistors are used everywhere: LED current limiting, voltage dividers, pull-up and pull-down networks, sensor biasing, filters, and transistor bias circuits. Being able to read a resistor directly helps during schematic review, repair, lab debugging, and quick component identification.
The color code is a compact way to calculate nominal resistance. Once the colors are decoded, the calculation is the same as any resistor value calculation: combine the significant digits and multiply by the multiplier band. Tolerance then tells the expected range around the nominal value.
What is a Resistor Color Code?
Bands
Bands are colored rings printed around the resistor body. Their position determines whether a color represents a digit, multiplier, tolerance, or temperature coefficient.
Digits
Digit bands provide the significant figures of the resistance value. A 4-band resistor has two digit bands, while 5-band and 6-band resistors usually have three.
Multiplier
The multiplier band scales the digit value. For example, red as a multiplier means ×100, while orange means ×1,000.
Tolerance and Tempco
Tolerance shows the allowed deviation from nominal resistance. The temperature coefficient, used on 6-band parts, shows resistance drift with temperature in ppm/°C.
Formula reference
Engineering Formula
All resistor color code systems use the same basic idea: read the significant digits, apply the multiplier, then apply tolerance.
4-band: value = (digit1 digit2) × multiplier5-band: value = (digit1 digit2 digit3) × multiplierminimum = nominal × (1 - tolerance)maximum = nominal × (1 + tolerance)Variable definitions
- Significant digits come from the first two or three bands.
- Multiplier converts the significant digits into ohms.
- Tolerance defines the expected resistance range.
- Temperature coefficient applies to 6-band precision resistors.
4-Band Resistor
A 4-band resistor uses band 1 and band 2 as significant digits, band 3 as the multiplier, and band 4 as tolerance. For brown, black, red, gold, the digits are 1 and 0, the multiplier is ×100, and the tolerance is ±5%, giving 1 kΩ ±5%.
5-Band Resistor
A 5-band resistor adds a third significant digit before the multiplier. This is common on precision resistors. Red, red, black, brown, brown gives 220 × 10 = 2.2 kΩ with ±1% tolerance.
6-Band Resistor
A 6-band resistor adds a temperature coefficient band after the tolerance band. These resistors are useful in precision circuits, measurement equipment, references, filters, and designs exposed to changing temperature.
Resistor Color Table
The same color can mean different things depending on its band position. Gold and silver are not digit colors, but they are common multiplier and tolerance colors.
| Color | Digit | Multiplier | Tolerance | Temp Coefficient |
|---|---|---|---|---|
| Black | 0 | ×1 Ω | — | 250 ppm/°C |
| Brown | 1 | ×10 Ω | ±1% | 100 ppm/°C |
| Red | 2 | ×100 Ω | ±2% | 50 ppm/°C |
| Orange | 3 | ×1 kΩ | ±3% | 15 ppm/°C |
| Yellow | 4 | ×10 kΩ | ±4% | 25 ppm/°C |
| Green | 5 | ×100 kΩ | ±0.5% | 20 ppm/°C |
| Blue | 6 | ×1 MΩ | ±0.25% | 10 ppm/°C |
| Violet | 7 | ×10 MΩ | ±0.1% | 5 ppm/°C |
| Gray | 8 | ×100 MΩ | ±0.05% | 1 ppm/°C |
| White | 9 | ×1 GΩ | — | — |
| Gold | — | ×0.1 Ω | ±5% | — |
| Silver | — | ×0.01 Ω | ±10% | — |
Worked Examples
Brown Black Red Gold
1 kΩ ±5%
Brown = 1, black = 0, red multiplier = ×100, so 10 × 100 = 1,000 Ω.
Yellow Violet Red Gold
4.7 kΩ ±5%
Yellow = 4, violet = 7, red multiplier = ×100, so 47 × 100 = 4,700 Ω.
Red Red Black Brown Brown
2.2 kΩ ±1%
Red, red, black form 220; brown multiplier = ×10, so 220 × 10 = 2,200 Ω.
Green Blue Black Orange Brown
560 kΩ ±1%
Green, blue, black form 560; orange multiplier = ×1,000, so the value is 560,000 Ω.
Brown Black Black Red Brown Red
10 kΩ ±1%, 50 ppm/°C
Brown, black, black form 100; red multiplier = ×100, brown tolerance = ±1%, and red temperature coefficient = 50 ppm/°C.
Common Mistakes
- Reading the resistor backwards.
- Ignoring tolerance when checking expected range.
- Confusing multiplier color with a digit color.
- Treating gold or silver as normal digit bands.
Engineering Tips
- Use a multimeter to verify important resistor values.
- Prefer datasheet markings when the part number is known.
- Watch for heat damage, faded bands, or dirty surfaces.
- Check tolerance before assuming exact resistance.
Practical Applications
- Repairing old through-hole boards.
- Sorting loose resistor inventory.
- Checking prototypes against a schematic.
- Identifying parts before measurement.
Related Calculator
AvailableResistor Color Code Calculator
Decode 4-band, 5-band, and 6-band resistor color codes with tolerance range and temperature coefficient.
Related Reference
Resistor Color Code Reference
Lookup color bands, multipliers, tolerance values, and temperature coefficients.
Resistor Series Reference
Reference table for preferred resistor values across common E-series.
E24 Series
Lookup page for common E24 nominal values used in general-purpose designs.
Tolerance Reference
Reference for tolerance bands and expected resistance ranges.
Related Guides
Understanding E-Series Resistors
Learn why preferred resistor values exist and when to use E12, E24, E96, and other E-Series.
Choosing Resistor Wattage
Guide to wattage, derating, temperature rise, and resistor reliability.
Related Blog
10 Common Resistor Selection Mistakes
Practical advice for avoiding resistor value, tolerance, package, and stability mistakes.
How to Identify Resistors on a PCB
Future article explaining practical resistor identification and lab workflow.
Common Resistor Selection Mistakes
Future article covering common resistor mistakes in prototypes and repairs.
Support reference
FAQ
How do you read a resistor color code?
Start from the band closest to one end of the resistor, read the digit bands first, then apply the multiplier band and tolerance band. A 6-band resistor adds a final temperature coefficient band.
How do I know which end of the resistor to read from?
The first band is usually closer to one end of the body. The tolerance band is often gold, silver, brown, or red and is usually spaced farther from the other bands.
What does a 4-band resistor show?
A 4-band resistor uses two significant digit bands, one multiplier band, and one tolerance band.
What is the difference between 4-band and 5-band resistors?
A 5-band resistor uses three significant digit bands instead of two, so it can show more precise nominal values before the multiplier and tolerance bands.
What does the gold band mean on a resistor?
Gold usually means a multiplier of 0.1 when it appears in the multiplier position, or ±5% tolerance when it appears as the tolerance band.
What does the silver band mean on a resistor?
Silver usually means a multiplier of 0.01 when used as a multiplier, or ±10% tolerance when used as the tolerance band.
What is the temperature coefficient band?
The temperature coefficient band appears on 6-band resistors and tells how much the resistance changes with temperature, usually in ppm/°C.
Should I trust the color bands or measure the resistor?
Use the color bands for identification, then verify critical values with a multimeter or datasheet. Old, heated, or damaged resistors can have faded bands or shifted resistance.
Further Reading
- Engineering Guides hub and Resistor Guides category.
- IEC 60062 marking codes for resistors and capacitors.
- Manufacturer resistor datasheets for tolerance and temperature coefficient details.
- ECParts Toolkit calculator category for resistor design and verification tools.
- Basic electronics references covering resistance, tolerance, and power rating.