Resistor Color Code Calculator
Decode a four-band resistor's resistance and tolerance range.
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What this tool does
Decode a four-band resistor's resistance and tolerance range. Four-band codes only; five-band resistors use three significant digits.
How to use the Resistor Color Code Calculator
- Enter or select first digit.
- Enter or select second digit.
- Enter or select multiplier.
- Enter or select tolerance.
- Read the calculated result; change any measurement to compare alternatives.
Formula
resistance=(10×first+second)×10^multiplier; range=resistance×(1±tolerance/100)
- first
- First digit
- second
- Second digit
- multiplier
- Multiplier
- tolerance
- Tolerance
Four-band codes only; five-band resistors use three significant digits.
Worked example
For resistor color code calculator, the following measurements illustrate the exact method: First digit: 4; Second digit: 7; Multiplier: 2; Tolerance: 5.
Inputs
- First digitYellow
- Second digitViolet
- MultiplierRed
- ToleranceGold ±5%
Result
- Resistance (ohms)4,700
- Minimum (ohms)4,465
- Maximum (ohms)4,935
Results explained
- Resistance (ohms)
- Resistance (ohms) from the formula above. Four-band codes only; five-band resistors use three significant digits.
- Minimum (ohms)
- Minimum (ohms) from the formula above. Four-band codes only; five-band resistors use three significant digits.
- Maximum (ohms)
- Maximum (ohms) from the formula above. Four-band codes only; five-band resistors use three significant digits.
Frequently asked questions
resistance=(10×first+second)×10^multiplier; range=resistance×(1±tolerance/100)
Four-band codes only; five-band resistors use three significant digits.
No. Electrical and HVAC results are estimates. Installation must comply with local codes and be checked by a qualified licensed professional.
Nameplate values, conductor temperature, power factor, efficiency, weather and actual installation conditions may differ from your entered assumptions.
Confirm units, manufacturer data and the formula's assumptions, then verify sizing with the equipment instructions and applicable local standards.