What are standard resistor values?

standard resistor values article

You may have noticed that certain values of resistors keep cropping up and some don’t exist. That is because there are standard resistor values. The values that were chosen were all to do with tolerances and manufacturing in the early days of electronics.

If you look at the E12 standard resistor values when resistors were commonly only of a 10% tolerance, the value of 82 Ohms could be 10% higher which would add on another 8.2 Ohms so it could be as high as 90.2 Ohms. The next value up on the E12 standard resistor values is 100 Ohms so it could be 10% lower which would take off 10 Ohms so it could actually be as low as 90 Ohms so technically it could be lower than a 82 Ohm resistor which we have just seen could be as high as 90.2 Ohms!

An 82 ohm resistor at 10% tolerance could be as low as 73.8 Ohms. The next value down on the E12 scale is 68 Ohms which could be as high as74.8 Ohms. This means that any value of resistor manufactured will fit somewhere in the range, so no manufactured resistors needed to be thrown away. The values shown in the tables below are just the figures, so 27 would refer to 27 Ohms 270 ohms and 270K etc.

As manufacturing techniques have improved the number of standard resistor values has increased and the original E6 series has progressed now to the E192. With the number of values becoming more precise the resistor code had to be overhauled as it wasn’t possible to indicate a 115K resistor using the old four band system. You can read about resistor colour codes here.

Listed below are the standard resistor values that are available.

E6 series

10

15

22

33

47

68

E12 series

10

33

12

39

15

47

18

56

22

68

27

82

E24 series

10

18

33

56

11

20

36

62​

12

22

39

68

13

24

43

75

15

27

47

82

16

30

51

91

E48 series

100

133

178

237

316

422

562

750

105

140

187

249

332

442

590

787

110

147

196

261

348

464

619

825

115

154

205

274

365

487

649

866

121

162

215

287

383

511

681

909

127

169

226

30

402

536

715

953

E96 series

100

115

133

154

178

205

237

274

316

365

422

487

562

649

750

866

102

118

137

158

182

210

243

280

324

374

432

499

576

665

768

897

105

121

140

162

187

215

249

287

332

383

442

511

590

681

787

909

107

124

143

165

191

221

255

294

340

392

453

523

604

698

806

931

110

127

147

169

196

226

261

301

348

402

464

536

619

715

825

953

113

130

150

174

200

232

267

309

357

412

475

549

634

732

845

976​

E192 series

100

115

133

154

178

205

237

274

316

365

422

487

562

649

750

866

101

117

135

156

180

208

240

277

320

370

427

493

569

657

759

876​

102

118

137

158

182

210

243

280

324

374

432

499

576

665

768

887​

104

120

138

160

184

213

246

284

328

379

437

505

583

673

777

898

105

121

140

162

187

215

249

287

332

383

442

511

590

681

787

909

106

123

142

164

189

218

252

291

336

388

448

517

597

690

796

920

107

124

143

165

191

221

255

294

340

392

453

523

604

698

806

931

109

126

145

167

193

223

258

298

344

397

459

530

612

706

816

942

110

127

147

169

196

226

261

301

348

402

464

536

619

715

825

953

111

129

149

172

198

229

264

305

352

407

470

542

626

723

835

965

113

130

150

174

200

232

267

309

357

412

475

549

634

732

845

976​

114

132

152

176

203

234

271

312

361

417

481

556

642

741

856

988