When to use this calculator
Decode a conventional resistor’s two digits and multiplier into resistance. A numeric decoding of a two-significant-digit resistor; enter the digits and multiplier from the colour bands.
Explore the dc circuits & components calculators for other questions in this topic. For a related calculation, use the Resistor Power Calculator: Calculate power dissipated as heat in a resistor.
PUTTING IT INTO PRACTICE
Resistor Colour Value: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| First digit (integer) | 4 |
| Second digit (integer) | 7 |
| Multiplier exponent (integer) | 2 |
| Result | 4,700 Ω |
- Check the input labels and enter the example values above.
- Apply the relationship: Nominal resistance = (10×first digit+second digit) × 10^multiplier.
- The result is 4,700 Ω, rounded for display.
How to interpret your result
A numeric decoding of a two-significant-digit resistor; enter the digits and multiplier from the colour bands.
Ideal component models omit tolerances, heat and parasitic effects. Distinguish nominal energy from usable energy for batteries. Component ratings and installation requirements need separate manufacturer and design checks.
Frequently asked questions
Can these calculations select a safe installation rating?
No. They explain ideal relationships and do not include every thermal, protective or regulatory requirement.
When is the resistor colour value calculator useful?
Decode a conventional resistor’s two digits and multiplier into resistance. A numeric decoding of a two-significant-digit resistor; enter the digits and multiplier from the colour bands.
How do I use the resistor colour value calculator?
Enter first digit (integer), second digit (integer), multiplier exponent (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Nominal resistance = (10×first digit+second digit) × 10^multiplier.
What should I check before using the result?
A numeric decoding of a two-significant-digit resistor; enter the digits and multiplier from the colour bands.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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