~ Preferred Component Value Calculator ~

Required Value
Tolerance ±
EIA Series E6
EIA Series E12
EIA Series E24
5% & 2% & 1%
EIA Series E48
2% & 1%
EIA Series E96
EIA Series E192
0.5% & 0.25% & 0.1%

The Electronic Industries Association (EIA) specifies standard values for components which I have always known as the "preferred values" that I learned from my dad an early age along with the colour code for reading them ~ which is much easier when you are taught the values are limited and repeat in decades

The series numbers E6 to E192 indicate the number of Exponential or logarithmic values in each decade ~ The E12 series found in most vintage equipment has values 10 12 15 18 22 27 33 39 47 56 68 82 then 100 120 150 . . . with a tolerance ±10% so any value +10% matches the next value up ‑10%

The value in the tolerance column dictates the series based on selecting resistors to fit "tolerance bins" so that none are wasted in manufacture ~ Nowadays manufacturing is more accurate and many makers supply higher tolerances than the series values would indicate

If you want to make an odd value from a series or parallel combination of 2 resistors then check this calculator  or click here for other calculators

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