Electronics CalculatorsE12 and E24 resistor values
You cannot buy a 4,600 ohm resistor in a normal shop. Resistor values come in steps.
The idea
Resistors are made with a tolerance, such as ±5% or ±10%. A series of values is chosen so that each value, with its tolerance, nearly touches the next one. A finer tolerance needs more values per decade. The E12 series has 12 values per decade (for ±10%) and E24 has 24 (for ±5%).
The values
| Series | Values in one decade (1 to 10) | Tolerance it is made for |
|---|---|---|
| E12 | 1, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2 | about ±10% |
| E24 | 1, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.7, 3, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, 9.1 | about ±5% |
Each list repeats in every power of ten: 10, 100, 1 k and 10 k, and 12, 120, 1.2 k, and so on. E12 is contained in E24.
About the source
These are the values printed in common references. The standard that defines the series, IEC 60063, is a paid document that we did not read.
Choosing a value
- Calculate the value you need.
- Find the standard values just below and above it.
- If the circuit is sensitive in one direction (an LED resistor, for example), choose the value on the safe side: for an LED it is the value above, which gives less current.
Our calculators for LED resistors and dividers do this for you, and the page on series and parallel resistors shows how to make an in-between value from two resistors.
Why 4.7 and not 4.6?
4.7 is in the series. 4.6 is not.
Are there finer series?
Yes: E48, E96 and E192 exist for 1% and finer parts. This site lists E12 and E24.
This is an independent guide. It is not connected with any standards body or company named here. The formulas are the usual textbook ones; the colour code, E-series and AWG values are those printed in common references, because the standards IEC 60062, IEC 60063 and ASTM B258 are paid documents that we did not read. Tables and examples were calculated with Python on 14 November 2026. Check data sheets and local safety rules before you build.