Resistor Color Code Calculator

Decode any resistor's color code to find its resistance value and tolerance.

Band 1 (1st digit)

Band 2 (2nd digit)

Band 3 (Multiplier)

Band 4 (Tolerance)

Band 1

Band 2

Band 3

Band 4 Mult

Band 5 Tol

Resistance

Tolerance

Min Value

Max Value

📖 What is a Resistor Color Code?

Resistors - the tiny components that limit current flow in electronic circuits - are usually too small to have their value printed in numbers. Instead, they use a standardised system of colour bands that encode the resistance value and tolerance. The resistor colour code was standardised by the Electronic Industries Alliance (EIA) and is used worldwide.

A 4-band resistor has two significant figure bands, one multiplier band, and one tolerance band. This encodes values to two significant figures, suitable for general-purpose resistors with ±5% or ±10% tolerance.

A 5-band resistor adds an extra significant figure, encoding the value to three significant figures. These are used for precision resistors with ±1% or better tolerance, where the extra digit provides more accurate specification.

Reading the code is simple once you know the colour-to-number mapping: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9. The multiplier band uses these plus gold (×0.1) and silver (×0.01). The tolerance band uses gold (±5%), silver (±10%), and colours for precision values.

📐 Formula

4-band: Value = (Band1 × 10 + Band2) × Multiplier

5-band: Value = (Band1 × 100 + Band2 × 10 + Band3) × Multiplier

Minimum Value = Resistance × (1 - Tolerance%)

Maximum Value = Resistance × (1 + Tolerance%)

📖 How to Use This Calculator

Select 4-band or 5-band depending on your resistor.

Choose the colour for each band from the dropdowns - in order from left to right.

Click Decode - resistance value, tolerance, and min/max range are shown.

💡 Example Calculations

Example 1 - 4-band: Brown-Black-Red-Gold

Band 1: Brown = 1, Band 2: Black = 0, Multiplier: Red = ×100, Tolerance: Gold = ±5%

Value = (1×10 + 0) × 100 = 1,000 Ω = 1 kΩ ±5%

Range: 950 Ω to 1,050 Ω

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Example 2 - 5-band: Red-Yellow-Orange-Red-Brown

D1: Red=2, D2: Yellow=4, D3: Orange=3, Multiplier: Red=×100, Tolerance: Brown=±1%

Value = (2×100 + 4×10 + 3) × 100 = 243 × 100 = 24,300 Ω = 24.3 kΩ ±1%

Range: 24,057 Ω to 24,543 Ω

Try this example →

Frequently Asked Questions

How do I read a resistor color code?+

For a 4-band resistor: Band 1 = first digit, Band 2 = second digit, Band 3 = multiplier (power of 10), Band 4 = tolerance. Read them in order from the band closest to the end of the resistor. Example: Brown-Black-Red-Gold = 1, 0, ×100, ±5% = 1000Ω ±5% = 1kΩ.

What is the difference between 4-band and 5-band resistors?+

4-band resistors have 2 significant figure bands + 1 multiplier + 1 tolerance. 5-band resistors have 3 significant figure bands + 1 multiplier + 1 tolerance, allowing more precise values. Precision resistors (1% or better) are usually 5-band.

What do the tolerance colors mean?+

Brown = ±1%, Red = ±2%, Green = ±0.5%, Blue = ±0.25%, Violet = ±0.1%, Gold = ±5%, Silver = ±10%, None = ±20%.

What is E24 series?+

Resistors come in standard values based on the E-series. E24 (24 values per decade) is common for ±5% tolerance resistors. Common values include: 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91 - and their multiples.

What if a resistor has no color bands at all?+

Plain resistors without color bands are typically fusible resistors or power resistors where the value is printed directly on the body. Some surface mount resistors (SMD) use a 3- or 4-digit numerical code instead of color bands.

How do you read a 4-band resistor color code?+

For a 4-band resistor: Band 1 = first significant digit. Band 2 = second significant digit. Band 3 = multiplier (number of zeros). Band 4 = tolerance. Color values: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9. Multipliers: Black=x1, Brown=x10, Red=x100, Orange=x1000, Yellow=x10000. Tolerances: Gold=5%, Silver=10%. Example: Red-Red-Brown-Gold = 2-2-x10-5% = 220 ohms 5%.

What are the standard resistor values (E-series)?+

Resistors are manufactured in standard E-series values rather than every possible number. E12 (12 values per decade, 10% tolerance): 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82 and their multiples. E24 (24 values, 5% tolerance) fills in between. E96 (96 values, 1% tolerance) provides finer increments. If you calculate a needed resistance of 427 ohms, the nearest E24 value is 430 ohms. This is why circuit design often requires standard values rather than exact calculated values.

How do I measure a resistor value without a color code?+

Use a digital multimeter (DMM) set to the resistance (ohms) mode. Touch the probes to both leads of the resistor - polarity does not matter for resistors. The display shows the resistance in ohms, kilohms, or megohms. For in-circuit measurements, power must be off and one lead should be lifted from the board to avoid parallel paths giving false readings. SMD (surface-mount) resistors use a 3 or 4-digit numerical code instead of color bands: the last digit is the multiplier (number of zeros to append), so 472 = 47 x 100 = 4700 ohms = 4.7 kilohms.

How do I read a 6-band resistor color code?+

6-band resistors add a temperature coefficient band after the tolerance band. Bands 1-3 are the three significant digits, band 4 is the multiplier, band 5 is tolerance, and band 6 is temperature coefficient (ppm per degree C). Brown = 100 ppm, Red = 50 ppm. Standard 4 and 5-band resistors are far more common; 6-band are used in precision applications.