Resistor Color Code Calculator for 3, 4, 5, and 6 band resistors. Decode resistance, tolerance, and temperature coefficient with formulas, examples, FAQs, and references.

Resistor Color Code Calculator

What this calculator does

The Resistor Color Code Calculator decodes 3, 4, 5, and 6-band axial resistors. It instantly calculates the resistance value, tolerance range, and temperature coefficient (for 6-band resistors).

Inputs explained

  • Number of bands: Select the total number of color bands on your resistor (3 to 6).
  • Band 1, 2, 3: The significant digit colors.
  • Multiplier band: The power of 10 multiplier applied to the digits.
  • Tolerance band: Indicates the possible percentage variation from the nominal value.
  • TCR band: (6-band only) The temperature coefficient of resistance in ppm/K.

How it works / Method

The standard IEC 60062 color code is used to translate band colors into numeric digits. The first 2 or 3 bands form a base number, which is multiplied by the multiplier band's value. The tolerance and TCR bands are then applied to determine the full specification.

Formulas used

  • 3-band: R = (D1·10 + D2) × Multiplier, tolerance = ±20%
  • 4-band: R = (D1·10 + D2) × Multiplier ± Tolerance%
  • 5-band: R = (D1·100 + D2·10 + D3) × Multiplier ± Tolerance%
  • Min = R − R × (Tolerance / 100)
  • Max = R + R × (Tolerance / 100)

Units: Resistance in Ohms (Ω), Tolerance in %, TCR in ppm/°C.

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Formulas

4-BandR = (D1·10 + D2) × Mul
5-BandR = (D1·100 + D2·10 + D3) × Mul
RangeMin/Max = R ± Tolerance

Quick Reference: Color Code

ColorDigitMultiplierTol
Black0×1-
Brown1×10±1%
Red2×100±2%
Orange3×1k-
Yellow4×10k-
Green5×100k±0.5%
Blue6×1M±0.25%
Violet7×10M±0.1%
Grey8×100M±0.05%
White9×1G-
Gold-×0.1±5%
Silver-×0.01±10%

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Step-by-step example

Scenario: You have a 4-band resistor with colors: Yellow, Violet, Red, Gold.

Formula: R = (Digit1·10 + Digit2) × Multiplier ± Tolerance%

  1. Digit 1 (Yellow) = 4
  2. Digit 2 (Violet) = 7
  3. Base value = 47
  4. Multiplier (Red) = 100
  5. Resistance = 47 × 100 = 4,700 Ω = 4.7 kΩ
  6. Tolerance (Gold) = ±5%
  7. Min/Max Range = 4,465 Ω to 4,935 Ω

Result: 4.7 kΩ ±5%

Use cases

  • Bench repair and component identification.
  • Prototyping breadboard circuits.
  • Verifying SMT or through-hole resistor readings.
  • Hobby electronics and DIY projects.
  • Education and learning electronic color codes.

Assumptions & limitations

  • Assumes standard IEC 60062 color coding.
  • Does not account for aging or overheating damage which may shift resistance values.
  • Color bands can sometimes fade or discolor, making them hard to read.
  • Measurement with a multimeter is always recommended for precise verification.
  • Consult local codes and a licensed professional for safety-critical electrical systems.

Sources & references

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Frequently Asked Questions

Read it left to right. Hold the resistor with the tolerance band (gold or silver) on your right. The first two bands are significant digits, the third is the multiplier (power of 10), and the fourth is tolerance. Example: brown-black-red-gold means 1, 0, ×100 = 1000 Ω = 1 kΩ ±5%. I tell my juniors to keep a printed code chart on the bench until the colors become second nature, because misreading red as orange happens to everyone in low light.

Gold and silver almost always sit in the tolerance position. Gold means ±5% accuracy, silver means ±10%. If gold or silver appears as the third band (the multiplier) instead, it represents a divider: gold = ×0.1 and silver = ×0.01, used for sub-ohm resistors like 4.7 Ω or 0.22 Ω. So check the orientation first; misplacing the gold band has caused several wrong builds in our lab.

Tolerance is a percentage of the nominal value, given by the last band: gold ±5%, silver ±10%, brown ±1%, red ±2%, green ±0.5%. Multiply the nominal resistance by the tolerance and you get the allowed range. Example: a 1 kΩ ±5% resistor can read anywhere between 950 Ω and 1050 Ω and still be in spec. For house dimmer circuits and LED drivers we usually pick ±1% so the brightness stays consistent across fittings.

A 4-band resistor uses two significant digits plus a multiplier and tolerance, while a 5-band one uses three significant digits plus multiplier and tolerance. The extra band gives you finer values like 4.99 kΩ instead of just 4.7 kΩ or 5.1 kΩ. Precision resistors (1% or better) are usually 5-band. So if you spot five color bands on a small body, treat the third one as a digit, not a multiplier — that mistake costs us hours of debugging.

A 10 kΩ resistor in the 4-band scheme reads brown-black-orange-gold (1, 0, ×1000, ±5%). In a 5-band 1% precision part, the same value is brown-black-black-red-brown (1, 0, 0, ×100, ±1%). Keep one of each in your sample box for quick comparison. Check it on the multimeter before soldering, especially in voltage-divider work, because a swapped 1 kΩ for 10 kΩ silently shifts your reference voltage.

Two common reasons. First, the resistor has a tolerance, so a 1 kΩ ±5% reading 985 Ω is still perfectly fine. Second, your meter leads themselves add resistance — usually 0.2 to 0.5 Ω. There's also temperature drift, oxidation on the leads, and parallel paths if the resistor is still in-circuit. Always lift one leg of the resistor off the board before measuring, and zero out the meter leads first when you are working in the milliohm range.

Yes, most online calculators handle 6-band resistors. The first three are digits, the fourth is the multiplier, the fifth is tolerance, and the sixth band is the temperature coefficient (TCR), measured in ppm per °C. The TCR matters when you build precision references, sensor circuits, or anything that runs hot. For normal house wiring projects we mostly ignore that band, but for instrumentation panels we always specify a low-TCR part.