Reference chart

Standard resistor values chart

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Resistors come in a fixed set of values, not every number. When a sum gives you 350 Ω, this chart shows the values you can actually buy, and which one to pick.

The E12 series

Most resistor kits carry the 12 values of the E12 series in every decade. Each decade repeats the same 12 numbers, ten times bigger:

Decade	Values
10 Ω to 82 Ω	10 Ω, 12 Ω, 15 Ω, 18 Ω, 22 Ω, 27 Ω, 33 Ω, 39 Ω, 47 Ω, 56 Ω, 68 Ω, 82 Ω
100 Ω to 820 Ω	100 Ω, 120 Ω, 150 Ω, 180 Ω, 220 Ω, 270 Ω, 330 Ω, 390 Ω, 470 Ω, 560 Ω, 680 Ω, 820 Ω
1 kΩ to 8.2 kΩ	1 kΩ, 1.2 kΩ, 1.5 kΩ, 1.8 kΩ, 2.2 kΩ, 2.7 kΩ, 3.3 kΩ, 3.9 kΩ, 4.7 kΩ, 5.6 kΩ, 6.8 kΩ, 8.2 kΩ
10 kΩ to 82 kΩ	10 kΩ, 12 kΩ, 15 kΩ, 18 kΩ, 22 kΩ, 27 kΩ, 33 kΩ, 39 kΩ, 47 kΩ, 56 kΩ, 68 kΩ, 82 kΩ
100 kΩ to 820 kΩ	100 kΩ, 120 kΩ, 150 kΩ, 180 kΩ, 220 kΩ, 270 kΩ, 330 kΩ, 390 kΩ, 470 kΩ, 560 kΩ, 680 kΩ, 820 kΩ
1 MΩ to 8.2 MΩ	1 MΩ, 1.2 MΩ, 1.5 MΩ, 1.8 MΩ, 2.2 MΩ, 2.7 MΩ, 3.3 MΩ, 3.9 MΩ, 4.7 MΩ, 5.6 MΩ, 6.8 MΩ, 8.2 MΩ

10 MΩ is usually the largest value in a kit.

The E24 series

Resistors with ±5% tolerance also come in the E24 series: the E12 values plus one more between each pair. The 24 values in each decade start with these numbers:

10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91

So the 1 kΩ decade runs 1 kΩ, 1.1 kΩ, 1.2 kΩ, 1.3 kΩ, 1.5 kΩ and on up to 9.1 kΩ.

The E96 series

Precision ±1% resistors come in the E96 series, 96 values per decade. Multiply each number by 0.1, 1, 10, 100 and so on: 499 can be 49.9 Ω, 499 Ω, 4.99 kΩ or 49.9 kΩ.


100	102	105	107	110	113	115	118
121	124	127	130	133	137	140	143
147	150	154	158	162	165	169	174
178	182	187	191	196	200	205	210
215	221	226	232	237	243	249	255
261	267	274	280	287	294	301	309
316	324	332	340	348	357	365	374
383	392	402	412	422	432	442	453
464	475	487	499	511	523	536	549
562	576	590	604	619	634	649	665
681	698	715	732	750	768	787	806
825	845	866	887	909	931	953	976

Picking a value

Work out the resistance you need with Ohm's law, then:

Round up for a resistor that limits current, such as an LED's. More resistance means a little less current, which is safe.
Pick the nearest for a voltage divider, then check the output with the values you chose. If it has to be close, use E96 parts.
Combine two when nothing is close enough: two resistors in series add up, two in parallel give less than either.

Free lesson

Now build it yourself

Each lesson comes in three short parts: see the idea, try it on a live board, then build it yourself, with quick checks as you go.

Try it yourself: free lesson

“Ohm's law” is lesson 5 of 6 in Copper Flats, Electronics World 1. Free with an account. Lessons unlock in order, so you’ll do the 4 before it first.

Or start from the very first lesson, no account needed

Work it out

The ideas behind it

Questions people ask

Why are resistor values like 47 and 68 instead of 50 and 70?

Each value is about the same percentage above the last, so the ranges they cover with their tolerance overlap with no gaps. In the E12 series each step is about 21% bigger, which suits ±10% parts; E24 steps are about 10%, for ±5% parts.

Which resistor values should I buy first?

An E12 kit from 10 Ω to 1 MΩ covers almost every beginner circuit. 220 Ω, 330 Ω, 1 kΩ, 4.7 kΩ and 10 kΩ are the ones you'll reach for most.

My sum gave 350 Ω. Which value do I use?

For a current-limiting resistor, round up to the next value in your series, here 390 Ω. A bit more resistance means a bit less current, which is the safe way to be wrong.

What is the E96 series for?

E96 values are for ±1% resistors, used when a value has to be close: precise voltage dividers, filters and gain-setting resistors. Their colour codes have three digit bands.