E-Series Resistor Finder (E12/E24/E96)
Nearest standard E12, E24 or E96 value to any target resistance, with neighbours and percentage error — IEC 60063.
If neither neighbour is close enough, combine two: a series pair from the same series usually gets within 0.5 %. Remember the part tolerance dominates — chasing a 0.1 % nominal error with ±5 % parts is pointless; switch to E96 ±1 % (or E192 ±0.1 %) when the ratio actually matters, e.g. feedback dividers.
E-Series Resistor Finder computes the nearest standard E12/E24/E96 value to any target resistance — free, instant and private in your browser. Designers turning calculated values into orderable part numbers use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About E-Series Resistor Finder (E12/E24/E96)
E-Series Resistor Finder computes the nearest standard E12/E24/E96 value to any target resistance using the standard engineering relation: E-series values are 10^(k/N) per decade, rounded per IEC 60063 — the tool scans neighbours and reports the error. Worked live: a computed 4.32 kΩ snaps to 4.3 kΩ in E24 (−0.5 %) or 4.32 kΩ exactly in E96. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use E-Series Resistor Finder (E12/E24/E96)
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use E-Series Resistor Finder (E12/E24/E96)?
- ✓Implements the real formula — E-series values are 10^(k/N) per decade, rounded per IEC 60063 — the tool scans neighbours and reports the error — with the substitution shown, not a black box
- ✓Built for designers turning calculated values into orderable part numbers
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate e-series resistor?+
The nearest standard E12/E24/E96 value to any target resistance follows E-series values are 10^(k/N) per decade, rounded per IEC 60063 — the tool scans neighbours and reports the error. For example, a computed 4.32 kΩ snaps to 4.3 kΩ in E24 (−0.5 %) or 4.32 kΩ exactly in E96. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
Why do resistors come in values like 4.7 and 6.8?+
Each E-series spaces values evenly on a log scale so that adjacent values overlap by the part tolerance — E12 (±10 %) needs 12 steps per decade, E24 (±5 %) needs 24. The 'odd' numbers are just 10^(k/N) rounded.
When is E96 worth the bother over E24?+
When a RATIO sets your accuracy: feedback dividers, gain-set pairs, references. A ±5 % part can't deliver a 1 % divider. For pull-ups, LED resistors and timing where ±5 % is fine, E24 keeps the BOM simpler and cheaper.
Is the E-Series Resistor Finder free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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