Resistor Color Code Converter
Decode four- or five-band resistors, or encode an exactly representable resistance. Inspect nominal value, tolerance range and a labelled band diagram.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Read two or three significant decimal digits, multiply by the power of ten encoded by the next band, and apply the final tolerance. Encoding searches the supported exponents for an exact integer significand of the selected length.
Nominal resistance=significant digits×10^multiplier; tolerance bounds=nominal×(1±tolerance/100)
Worked example
Yellow–violet–red–gold is 47×100=4700 ohms with ±5% tolerance, giving 4465–4935 ohms. Red–orange–violet–black–brown is 237 ohms ±1%.
Assumptions and input details
Standard four/five-band digit, multiplier and tolerance interpretation, following the linked Vishay chart. Read from the significant-digit end; no photo recognition is attempted. The first digit cannot be black. Gold and silver multipliers are ×0.1 and ×0.01. No-band tolerance means ±20% and is allowed only with the four-band scheme. Temperature-coefficient bands, zero-ohm jumpers, SMD markings, reliability bands and special manufacturer codes are excluded. Encoding requires an exact two/three-digit representation; it does not round to an E-series value. Displayed band colors are illustrative and always accompanied by their names.
References: Vishay color-code reference
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
SI prefixes are explicit: for example, milli means one thousandth, micro one millionth and kilo one thousand. Changing a unit changes the interpretation of the entered number.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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