Resistor Combination Finder
Search entered resistor values for the closest one- or two-part series/parallel target, with a common tolerance range.
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
Enumerate all singles and permitted unordered pairs in series/parallel, then sort by nominal relative target error.
Series R=R1+R2; parallel R=1/(1/R1+1/R2)
Worked example
With 100,220,330,470,1000 Ω available, 220 Ω parallel with 470 Ω gives about 149.855072 Ω, close to a 150 Ω target.
Assumptions and input details
1–100 positive resistor rows. Reuse disabled treats duplicate values on separate rows as distinct physical stock. Only one or two components are considered; ranking prefers smaller absolute nominal error then fewer parts. Common 0–50% tolerance gives a monotonic worst-case resistance interval, not a statistical yield. Power dissipation, temperature, procurement, layout and safety ratings are excluded.
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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