Decode 4, 5, or 6-band resistor color codes to find resistance, tolerance, and temperature coefficient. Visual resistor diagram included.
The resistor color code is a system of colored bands painted on resistors to indicate their resistance value, tolerance, and sometimes temperature coefficient. Each band\'s color corresponds to a digit, multiplier, or tolerance value according to an international standard originally developed by the Radio Manufacturers Association (RMA) and now maintained by IEC 60062.
Through-hole resistors use 4, 5, or 6 bands. Four-band resistors encode two significant digits plus a multiplier and tolerance, yielding values in the standard E12 or E24 series. Five-band resistors add a third significant digit for higher precision, following the E48 or E96 series. Six-band resistors include an additional band for the temperature coefficient of resistance (TCR), which is important in precision and high-reliability applications.
This calculator decodes any 4, 5, or 6-band resistor. Select each band\'s color from the dropdowns and instantly see the resistance value, tolerance range, and a visual representation of the resistor. The full color code reference table is provided below for quick lookup. Whether you\'re a student learning electronics fundamentals or a technician verifying components on a PCB, this tool makes resistor identification fast and error-free.
Manually decoding resistor color bands is error-prone, especially when colors look similar or the band order is ambiguous. This calculator eliminates guesswork by showing the decoded value, tolerance range, and a visual diagram in real time. It supports all three common band configurations (4, 5, 6) and includes a comprehensive reference table so you can quickly look up any color\'s meaning.
R = (D1 × 10 + D2) × 10^M for 4-band; R = (D1 × 100 + D2 × 10 + D3) × 10^M for 5/6-band. D = digit value, M = multiplier exponent.
Result: 1 kΩ ±1% (990 Ω to 1.01 kΩ)
100 × 10 = 1000 Ω = 1 kΩ. With ±1% tolerance the actual value is between 990 Ω and 1010 Ω.
The resistor color code was introduced in the 1920s by the Radio Manufacturers Association (RMA) and later adopted as an international standard (IEC 60062). Each color corresponds to a digit (0–9), and the same colors serve double duty as multiplier values, tolerance indicators, and temperature coefficients. The system is elegant: with just 12 colors, it can encode resistance values spanning over ten orders of magnitude.
The band closest to one end of the resistor is Band 1. If you cannot identify which end is which, look for the tolerance band — gold and silver are distinctive. If the resistor has no tolerance band, it is a ±20% part (rare in modern electronics). Five and six-band resistors always have three significant-digit bands followed by a multiplier. The tolerance band is typically the widest or most separated from the digit bands.
Resistor values follow preferred number series defined by IEC 60063. The E12 series (12 values per decade: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) is used for ±10% parts. The E24 series adds intermediate values for ±5% tolerance. E48 and E96 series provide 48 and 96 values per decade respectively, and require 5-band coding. Choosing the correct series is essential when designing circuits — you must select values that actually exist as standard components.
Start reading from the band closest to one end of the resistor body. The tolerance band (gold or silver) is usually the last band and has a slightly wider gap from the others.
Four-band resistors use two significant digits (1% precision steps in E96 series are not available), while five-band resistors use three significant digits, allowing finer precision values like 1.00 kΩ, 1.02 kΩ, etc.
The sixth band indicates how much the resistance changes per degree Celsius of temperature change. A brown band means 100 ppm/°C — for every 1°C change, resistance changes by 100 parts per million.
Colors can look similar under different lighting. Brown and red, orange and yellow, and blue and violet are commonly confused. Use a multimeter to verify when in doubt.
No tolerance band means ±20% tolerance. These are older, low-precision resistors rarely used in modern circuits.
No. SMD resistors use a numeric code printed on the component (e.g., "103" means 10 × 10³ = 10 kΩ). The color band system is used only on through-hole (axial lead) resistors.