Electronics Calculator

Resistor Color Code Decoder

Quickly decode 4-band resistor color codes into exact resistance and tolerance values

1st Band
2nd Band
Multiplier
Tolerance
Decoded Resistance
1.0 kΩ ± 5%
Exact Value: 1,000 Ω
Range: 950 Ω – 1,050 Ω
1 1st Digit Brown (1)
2 2nd Digit Black (0)
3 Multiplier Red (×100)
4 Tolerance Gold (±5%)
Common Standard Values
Resistor Color Code Reference Chart View Table ▾
Color Significant Digit Multiplier Tolerance
Black 0 ×1 Ω —
Brown 1 ×10 Ω ±1%
Red 2 ×100 Ω ±2%
Orange 3 ×1 kΩ —
Yellow 4 ×10 kΩ —
Green 5 ×100 kΩ ±0.5%
Blue 6 ×1 MΩ ±0.25%
Violet 7 ×10 MΩ ±0.1%
Gray 8 ×100 MΩ ±0.05%
White 9 ×1 GΩ —
Gold — ×0.1 Ω ±5%
Silver — ×0.01 Ω ±10%

How to Read a 4-Band Resistor Color Code

In your engineering labs, resistors are the most common passive electronic components you will encounter. Because axial through-hole resistors are tiny, their electrical resistance values cannot be easily printed as numbers. Instead, manufacturers print colored rings called color bands. A 4-band resistor indicates its nominal resistance in Ohms (Ω) and its manufacturing tolerance percentage.

Step-by-Step Decoding Process

Step 1: Orient the resistor correctly. Turn the resistor so that the metallic band (usually Gold or Silver) is positioned on your far right. This separated band represents the tolerance. You will always read the bands from left to right.
Step 2: Note the significant digits (Bands 1 & 2). The first band gives you the first digit (tens place), and the second band gives you the second digit (units place). For instance, if Band 1 is Red (2) and Band 2 is Violet (7), your base two-digit number is 27.
Step 3: Apply the multiplier (Band 3). The third band specifies the power of ten (10n) by which you multiply your two-digit number. If Band 3 is Orange (103 or ×1,000), multiply 27 × 1,000 = 27,000 Ω (27 kΩ).
Step 4: Check tolerance (Band 4). The fourth band indicates the precision limit. A Gold band represents ±5% tolerance. A 27 kΩ resistor with a ±5% tolerance can measure anywhere between 25.65 kΩ and 28.35 kΩ on a digital multimeter (DMM).

Standard 4-Band Color Code Chart

Color Digit (Bands 1 & 2) Multiplier (Band 3) Tolerance (Band 4)
Black0×1 Ω (100)—
Brown1×10 Ω (101)±1%
Red2×100 Ω (102)±2%
Orange3×1 kΩ (103)—
Yellow4×10 kΩ (104)—
Green5×100 kΩ (105)±0.5%
Blue6×1 MΩ (106)±0.25%
Violet7×10 MΩ (107)±0.1%
Gray8×100 MΩ (108)±0.05%
White9×1 GΩ (109)—
Gold—×0.1 Ω (10-1)±5%
Silver—×0.01 Ω (10-2)±10%

Quick Lab Mnemonic: To quickly memorize the sequence from 0 to 9, remember: "B.B. R.O.Y. of Great Britain had a Very Good Wife." Before soldering components or powering on your prototype circuit, always confirm your calculated value with an ohmmeter!