E-Series Value Calculator

How to use

1. 1Choose the component type: resistor, capacitor, or inductor.
2. 2Pick the E-series to match the tolerance you are buying, for example E24 for 5% or E96 for 1% parts.
3. 3Type the exact value your calculation produced and select its unit, such as kΩ, nF, or µH.
4. 4Read the nearest standard value, highlighted, along with the next value below and above and the percentage error of each.
5. 5Check the error chip colour: green means snapping stays inside the series tolerance, amber and rose mean the error is larger.
6. 6If no single value is close enough, use the two-component pairs to hit the target more precisely, and copy any result.

About this tool

E-Series Value Calculator rounds any value your design math produces to the nearest value you can actually buy, entirely in your browser. Resistors, capacitors, and inductors are manufactured only in the preferred values of the IEC 60063 standard, the E-series. Each series fills one decade with a fixed count of values spaced on a logarithmic scale so that, allowing for the part tolerance, adjacent values just about touch and cover the whole decade. E3 gives 3 values per decade, E6 gives 6, E12 gives 12, E24 gives 24, E48 gives 48, E96 gives 96, and E192 gives 192, with the looser series matching wider tolerances (E24 is the classic 5% grid, E96 is the 1% grid) and every lower series being exactly every other value of the next finer one. The recurring problem this solves is simple: a voltage divider ratio, an RC filter cutoff, an LED current resistor, or a reactance calculation almost never lands on a stocked value. It produces something like 4823 ohms, and the next step is always to ask what the nearest standard value is and how much error snapping to it introduces. Enter the exact value, pick the component type and the E-series, and the tool returns the nearest preferred value plus the next standard value below and above, each with a signed percentage error relative to your target. A coloured chip tells you at a glance whether that error stays inside the series tolerance band: green is within tolerance, amber is up to twice it, and rose is further out, which is your cue to choose a finer series or combine two parts. The decade handling is automatic, so the same grid works whether you are placing a 12 ohm resistor, a 4.7 kilohm resistor, a 1.5 megohm resistor, a 47 picofarad capacitor, or a 10 microhenry inductor; the values repeat every decade, so multiplying or dividing any standard value by ten gives another stocked value. When a single part is not close enough, the two-component combiner searches the chosen series across several decades for the best pair: two in series that add for resistors and inductors, two in parallel that add for capacitors, and the reciprocal arrangement for the opposite case, each shown with its resulting value and error and a copy button for the pair. The series reference chart lists every value in the decade you are working in and highlights the nearest match, so you can see the whole grid at once. Useful for analog and power design, filter and timing circuits, sensor front ends, calibrating gain and divider ratios, picking pull-up and current-limit resistors, and learning how the E-series grids and tolerances relate. All values are the published IEC 60063 tables and all math runs locally, so nothing you enter is uploaded, logged, or sent anywhere.

Free to use. Works in your browser. No signup, no login.