Resistor color code calculator

Read four-band and five-band resistors. Calculate nominal resistance, tolerance and the minimum and maximum values.

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Set your data

Number of bands

First digit

Second digit

Third digit

Multiplier

Tolerance

Four or five bands, with a nonzero first digit. No sixth band, SMD markings or voltage/current calculations.

Result

Enter your values to see the result.

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How to use it

Four bands represent two digits, a multiplier and tolerance. Five bands use three digits instead. Gold and silver can be fractional multipliers; the position of a color determines its role.

Example inputs
Input	Result
Yellow, Violet, Red, Gold	4700 Ω; 4465–4935 Ω

Method and limits

The first two or three bands form an integer multiplied by the power of ten represented by the next band. Tolerance applies above and below the nominal value.

Example

Usage scenario

Input: Yellow, Violet, Red, Gold
Result: $4465 Ω \leq R \leq 4935 Ω$

Calculation steps

Calculate nominal resistance
$47 \times 100 = 4700$
Calculate the tolerance margin
$4700 \times 0.05 = 235$
Subtract the margin for the minimum
$4700 - 235 = 4465$
Add the margin for the maximum
$4700 + 235 = 4935$

Yellow, violet, red and gold give 47 multiplied by 100, or 4700 Ω, equivalent to 4.7 kΩ. A 5% tolerance amounts to 235 Ω, giving a nominal tolerance interval from 4465 to 4935 Ω.

What are the limits of this tool?

Four or five bands, with a nonzero first digit. No sixth band, SMD markings or voltage/current calculations.

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Sources

SparkFun — Resistors

PRACTICAL GUIDES

How to read four-band and five-band resistors

Find the reading direction, separate digits, multiplier and tolerance and check a worked 4.7 kΩ resistor example.

Follow the steps