Resistor Color Code Calculator
Select the color of each band to read the value and tolerance of a through-hole resistor.
How to use the Resistor Color Code Calculator
- Choose the number of bands.
- Choose the band 1 (1st digit).
- Choose the band 2 (2nd digit).
- Choose the band 3 (3rd digit).
- Choose the multiplier band.
- Choose the tolerance band.
- Press Calculate. The result updates automatically as you type.
About the Resistor Color Code Calculator
Through-hole resistors are too small to print a value on, so they carry colored bands instead. Hold the resistor so the bands bunched toward one end are on the left; the tolerance band, often gold or silver, usually sits slightly apart on the right. Four-band resistors are common for 5% and 10% parts, while precision 1% parts use five bands for an extra significant digit.
If you are unsure of the direction, read it both ways: only one reading usually gives a standard E-series value such as 4.7 kΩ or 220 Ω. When colors are hard to tell apart, brown versus red or orange, confirm with a multimeter.
Formula
4-band: R = (10 × d₁ + d₂) × multiplier
5-band: R = (100 × d₁ + 10 × d₂ + d₃) × multiplier
Digit colors: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8, white 9. The multiplier is 10 raised to the color's digit (gold = 0.1, silver = 0.01). Example: yellow-violet-red-gold = 47 × 100 = 4,700 Ω ±5%.
Example calculation
Using the default values:
- Number of bands = 4 bands
- Band 1 (1st digit) = Yellow
- Band 2 (2nd digit) = Violet
- Multiplier band = Red ×100
- Tolerance band = Gold ±5%
the calculator returns:
- Resistance: 4.7 kΩ
- Tolerance: ±5%
- Range: 4.465 kΩ to 4.935 kΩ
- Value in ohms: 4,700 Ω
Frequently asked questions
How do I know which end to start reading from?
Start from the band closest to a lead. The tolerance band (gold, silver, or a wider gap before it) goes on the right. Gold and silver never appear as the first band.
What does brown-black-red mean?
Brown 1, black 0, red ×100: 10 × 100 = 1,000 Ω, or 1 kΩ.
What is a 6-band resistor?
It is a 5-band code plus a sixth band giving the temperature coefficient in ppm/°C. Ignore the sixth band and use the 5-band setting to read the resistance.
Last updated: · Category: Electrical calculators