SMD Resistor Code Calculator

Below is an SMD resistor code calculator. Enter the code printed on the resistor and it immediately works out the resistance, the type of marking and the typical tolerance. It also shows which standard series the value belongs to and how the same value is written in the other marking systems.

How to read the codes

SMD resistors are too small for color bands, so the value is printed on them as a short code of three or four characters. Four systems are in use:

3 digits (e.g. 472): the first two digits are the value and the third is the number of zeros to add. 472 is 47 followed by two zeros, so 4700 Ω = 4.7 kΩ. Typical for ±5% resistors.
4 digits (e.g. 4701): the first three digits are the value and the fourth is the number of zeros. 4701 is 470 followed by one zero = 4.7 kΩ. Typical for ±1% resistors.
R as decimal point (e.g. 4R7, R47): for values below 10 Ω, or 100 Ω with four characters. The letter R takes the place of the decimal point: 4R7 = 4.7 Ω, R47 = 0.47 Ω, 10R0 = 10 Ω.
EIA-96 (e.g. 01C): two digits give the position of the value in the E96 standard series, and the letter is a multiplier. 01 is 100 and C multiplies by 100, so 01C = 10 kΩ. Used on the smallest ±1% resistors, where four digits do not fit.

The codes 0, 00, 000 and 0000 mark a jumper (0 Ω), used as a bridge on the circuit board.

The ambiguous letter R

The letter R is used both as a decimal point and as the EIA-96 multiplier ×0.01. The code 47R usually means 47 Ω, but it can also be the EIA-96 code for 3.01 Ω. In that case the calculator shows both readings. Decide from the other resistors on the board, or measure the resistance with a multimeter.

EIA-96 multipliers

Letter	Multiplier	Example
Z	×0.001	`01Z` = 0.1 Ω
Y or R	×0.01	`01Y` = 1 Ω
X or S	×0.1	`01X` = 10 Ω
A	×1	`01A` = 100 Ω
B or H	×10	`01B` = 1 kΩ
C	×100	`01C` = 10 kΩ
D	×1000	`01D` = 100 kΩ
E	×10,000	`01E` = 1 MΩ
F	×100,000	`01F` = 10 MΩ

EIA-96 codes

Multiply the base by the multiplier from the table above. For example, 68X is 499 × 0.1 = 49.9 Ω.

Code	Base	Code	Base	Code	Base	Code	Base
01	100	25	178	49	316	73	562
02	102	26	182	50	324	74	576
03	105	27	187	51	332	75	590
04	107	28	191	52	340	76	604
05	110	29	196	53	348	77	619
06	113	30	200	54	357	78	634
07	115	31	205	55	365	79	649
08	118	32	210	56	374	80	665
09	121	33	215	57	383	81	681
10	124	34	221	58	392	82	698
11	127	35	226	59	402	83	715
12	130	36	232	60	412	84	732
13	133	37	237	61	422	85	750
14	137	38	243	62	432	86	768
15	140	39	249	63	442	87	787
16	143	40	255	64	453	88	806
17	147	41	261	65	464	89	825
18	150	42	267	66	475	90	845
19	154	43	274	67	487	91	866
20	158	44	280	68	499	92	887
21	162	45	287	69	511	93	909
22	165	46	294	70	523	94	931
23	169	47	301	71	536	95	953
24	174	48	309	72	549	96	976

Resistors without a marking

On the smallest packages, 0402 (1.0 × 0.5 mm) and below, the code is usually no longer printed because there is no room for it. The value can then only be found from the circuit documentation or by measuring, with the resistor removed from the circuit.

Standards and sources

R as a decimal point is part of the RKM code in IEC 60062 (Marking codes for resistors and capacitors), the same standard that defines the color code for banded resistors.
The E6–E192 standard series, including the E96 series that EIA-96 is based on, are defined in IEC 60063.
Manufacturers always list the marking of their series in the datasheet. That is the most reliable confirmation, especially for unusual codes.

Code	Base	Code	Base	Code	Base	Code	Base
01	100	25	178	49	316	73	562
02	102	26	182	50	324	74	576
03	105	27	187	51	332	75	590
04	107	28	191	52	340	76	604
05	110	29	196	53	348	77	619
06	113	30	200	54	357	78	634
07	115	31	205	55	365	79	649
08	118	32	210	56	374	80	665
09	121	33	215	57	383	81	681
10	124	34	221	58	392	82	698
11	127	35	226	59	402	83	715
12	130	36	232	60	412	84	732
13	133	37	237	61	422	85	750
14	137	38	243	62	432	86	768
15	140	39	249	63	442	87	787
16	143	40	255	64	453	88	806
17	147	41	261	65	464	89	825
18	150	42	267	66	475	90	845
19	154	43	274	67	487	91	866
20	158	44	280	68	499	92	887
21	162	45	287	69	511	93	909
22	165	46	294	70	523	94	931
23	169	47	301	71	536	95	953
24	174	48	309	72	549	96	976

Code	Base	Code	Base	Code	Base	Code	Base
01	100	25	178	49	316	73	562
02	102	26	182	50	324	74	576
03	105	27	187	51	332	75	590
04	107	28	191	52	340	76	604
05	110	29	196	53	348	77	619
06	113	30	200	54	357	78	634
07	115	31	205	55	365	79	649
08	118	32	210	56	374	80	665
09	121	33	215	57	383	81	681
10	124	34	221	58	392	82	698
11	127	35	226	59	402	83	715
12	130	36	232	60	412	84	732
13	133	37	237	61	422	85	750
14	137	38	243	62	432	86	768
15	140	39	249	63	442	87	787
16	143	40	255	64	453	88	806
17	147	41	261	65	464	89	825
18	150	42	267	66	475	90	845
19	154	43	274	67	487	91	866
20	158	44	280	68	499	92	887
21	162	45	287	69	511	93	909
22	165	46	294	70	523	94	931
23	169	47	301	71	536	95	953
24	174	48	309	72	549	96	976

Code	Base	Code	Base	Code	Base	Code	Base
01	100	25	178	49	316	73	562
02	102	26	182	50	324	74	576
03	105	27	187	51	332	75	590
04	107	28	191	52	340	76	604
05	110	29	196	53	348	77	619
06	113	30	200	54	357	78	634
07	115	31	205	55	365	79	649
08	118	32	210	56	374	80	665
09	121	33	215	57	383	81	681
10	124	34	221	58	392	82	698
11	127	35	226	59	402	83	715
12	130	36	232	60	412	84	732
13	133	37	237	61	422	85	750
14	137	38	243	62	432	86	768
15	140	39	249	63	442	87	787
16	143	40	255	64	453	88	806
17	147	41	261	65	464	89	825
18	150	42	267	66	475	90	845
19	154	43	274	67	487	91	866
20	158	44	280	68	499	92	887
21	162	45	287	69	511	93	909
22	165	46	294	70	523	94	931
23	169	47	301	71	536	95	953
24	174	48	309	72	549	96	976