Resistor Color Code Calculator
Each color band is a digit or multiplier: Black=0, Brown=1 ... White=9, Gold=×0.1 (or ±5%), Silver=×0.01 (or ±10%)
Select the color bands on your resistor to decode its resistance value and tolerance range. Supports standard 4-band resistors (typically ±5%) and precision 5-band resistors (±1% and ±2%). For Ohm's Law checks with that value, try the Ohm's Law calculator.
Resistance: 560 Ω ±5%
Range: 532 Ω – 588 Ω
How to read resistor color bands
Resistors use colored bands to indicate their value because printing precise numbers on a small cylindrical component is impractical. The standard EIA system uses two or three significant-digit bands, a multiplier band, and a tolerance band. 4-band resistors are the most common type in hobby and general-purpose kits; 5-band resistors appear in precision electronics, audio equipment, and measurement circuits.
To read a 4-band resistor: Band 1 is the first digit, Band 2 is the second digit, Band 3 is the multiplier (a power of 10), and Band 4 is the tolerance. The tolerance band is usually gold (±5%) or silver (±10%) and has a slightly larger gap before it to help identify the reading direction.
To read a 5-band resistor: Bands 1, 2, and 3 are the three significant digits, Band 4 is the multiplier, and Band 5 is the tolerance. 5-band resistors typically have brown (±1%) or red (±2%) tolerance bands. When the tolerance band color could be confused with a digit band, look for the band that is offset or slightly wider.
- Band 1: First significant digit (black, which represents 0, is not used as the first band)
- Band 2: Second significant digit
- Band 3: Third digit (5-band) or multiplier (4-band)
- Band 4: Multiplier (5-band) or tolerance (4-band)
- Band 5: Tolerance (5-band only)
Hold the resistor so the gold or silver tolerance band faces right. Read the remaining bands from left to right.
How to convert
4-band value formula
Combine the two digit bands and the multiplier to get the resistance.
R = (Band1 × 10 + Band2) × Multiplier
Example: Brown(1), Black(0), Red(×100) = 10 × 100 = 1,000 Ω = 1 kΩ
5-band value formula
Precision resistors add a third digit band for more specific values.
R = (Band1 × 100 + Band2 × 10 + Band3) × Multiplier
Example: Brown(1), Black(0), Black(0), Brown(×10) = 100 × 10 = 1,000 Ω = 1 kΩ
Tolerance range calculation
The tolerance band defines the acceptable range around the nominal value.
Min = R × (1 - tolerance / 100)
Max = R × (1 + tolerance / 100)
Example: 1 kΩ ±5% = 950 Ω to 1,050 Ω
Worked examples
Question: What is the value of a 4-band resistor: Brown, Black, Orange, Gold?
Solution: Brown(1), Black(0), Orange(×1,000), Gold(±5%) = 10 × 1,000 = 10,000 Ω = 10 kΩ ±5%
Question: A 5-band resistor has bands: Red, Red, Black, Brown, Brown. What is its value?
Solution: Red(2), Red(2), Black(0), Brown(×10), Brown(±1%) = 220 × 10 = 2,200 Ω = 2.2 kΩ ±1%
Question: What is the tolerance range for a 4.7 kΩ ±5% resistor?
Solution: Min = 4,700 × 0.95 = 4,465 Ω; Max = 4,700 × 1.05 = 4,935 Ω
Common mistakes and notes
- The tolerance band (gold or silver) always faces right when reading bands left to right.
- If a resistor reads the same value in both directions, use a multimeter on the resistance (Ω) setting to confirm the actual value.
- Gold and silver only appear as multiplier bands (×0.1, ×0.01) or tolerance bands, never as first or second digit bands.
- Most general-purpose resistors are 4-band; 5-band are common in precision electronics, audio, and measurement instruments.
Assumptions
- Supports standard 4-band (EIA) and 5-band (precision) color codes.
- Component tolerance applies to the nominal value at standard temperature (25°C).
- Military 6-band resistors (with temperature coefficient) are not covered.
Worked example
Example: Green (5), Blue (6), Brown (×10), Gold (±5%) = 560 Ω ±5% (range: 532 Ω to 588 Ω).
FAQ
What does each resistor color represent?
Each color represents a digit: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9. Gold and Silver are used only as multipliers (×0.1, ×0.01) or tolerance bands (±5%, ±10%).
How do I know which end to start reading from?
The tolerance band (gold or silver on a 4-band; usually brown on a 5-band) is offset with a slightly larger gap from the other bands. Hold the resistor with the tolerance band on the right and read the remaining bands left to right.
What is the difference between a 4-band and 5-band resistor?
A 4-band resistor has two significant digits plus a multiplier and tolerance. A 5-band resistor has three significant digits, providing more precise values. 5-band resistors typically come in tighter tolerances, ±1% and ±2% versus the ±5% common in 4-band types.
My resistor has 6 bands. What is the 6th band?
The 6th band indicates the temperature coefficient of resistance (TCR), how much resistance changes per degree Celsius. Brown = 100 ppm/°C, Red = 50 ppm/°C. These are used in precision and military-grade components.
Can I just measure the resistance instead of reading bands?
Yes, a digital multimeter on its resistance (Ω) setting reads the actual value directly. This is more reliable than interpreting faded, damaged, or ambiguous color bands on older components.
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⚠️ Sanity Check Only
This tool provides informational estimates only. It is not professional engineering advice. Electrical work is dangerous and governed by strict local codes.
Before you start:
- Verify these results with a licensed electrician.
- Cross-reference with the latest Electrical Code (NEC/CEC).
- Never work on live circuits.