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Inductor Color Codes – How To Read Inductor Value? Calculator

How to know the Value of Inductance of an Inductor using Standard & Color Codes – Calculators & Examples

Reading Value of Inductor Marking Codes

For small Inductors like air-core, iron-core, ferrite-core or SMD inductors etc., the surface area of the component is very small hence it is not possible to print the exact value of inductance and other parameters (nameplate rating) on it. This way, some special notations and marking are used e.g. color bands, color dots, digits, numbers and alphanumeric characters which known as inductor color codes and they are used to indicates the different characteristics and values of inductance of inductors. Generally, the values of these indictors are in μH (Microhenries 1 x 10-6).

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Let see how to read the value of inductors by using the standard marking codes?

How to Read the Inductor Value from Marking Dots, Standard & Color Codes

2 Numerical Values:

If an inductor has two numerical values, or any two digits and a letter like 11N, it means the value is 11 nH (nanohenry).

  • If there is a letter (mostly R which shows dot “.”) in the middle of two digits like 6R8, it shows:

For example: 6R8 = 6.8 μH.

  • If the first or middle letter is “μ”, “p” or “n” instead of R, it represents the main units of Inductance such as

For examples:

  • 5μ = 5 Micro-henry
  • 3μ1 = 3.1 Micro-henry
  • N42 = 42 Nano-henry

Inductor Standard Marking Codes

3 Numerical Values:

Most of the inductors have three numerical values printed on it. For example, 220, 221, 222, 223, 331, 332 etc. Let’s see how to read these values. Suppose the printed value on an inductor is “332”

  • 332 = 33 x 102 = 3300 μH (Microhenry)

Similarly, if the specials marking code on the inductor is 223J: (3 Digits + 1 Alphabet), the fourth one character (“J” in this case) shows the tolerance of the inductor: For example:

  • 223J = 22 x 103 = 22 + 3 Zeros = 22,000 µH = 22mH
  • The Letter “J” shows a tolerance of ±5 %.
  • Hence the value of inductance is = 22mH, ±5 %

Inductor Standard Marking Code - Example

Tolerance of Inductors

There are Capital letters printed on the inductors except the value of inductance such as 223J.

The following table shows the tolerance for inductors indicated by Letters.

Letters Tolerance in %
B ±0.15 nH
C ±0.2 nH
S ±0.3 nH
D ±0.5 nH
F ±1%
G ±2%
H ±3%
J ±5 %
K ±10%
L ±15%
M ±20%
V ±25%
N ±30%

The following symbols and units are used to represent the values of inductance of indictor in  Millihenries (mH), Microhenries (μH) & Nanohenries (nH).

Symbol Abbreviation Value in Numbers
mH Milli-henry 10-3
μH Micro-henry 10-6
nH Nino-henry 10-9

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Inductor Color Codes

Apart from the text marking on inductors, there are special inductor color codes namely “EIA” (Electronic Industries Association) and “Mil-Spec” (Military Specification). There are three, four or five color bands printed on the inductor which shows the inductance of the inductor and tolerance. Let’s see how to read 2, 3 and 4 bands color codes inductor as follows:

Reading 3 bands Inductor Color Codes

If there are three color bands marked on an inductor, it means

  • 1st Color Band = First Number of Value of Inductor.
  • 2nd Color Band = Second Number of value of Inductor.
  • 33rd Color Band = The number of Zeros (as multiplier) with the first two digits of inductor (In numbers).
Example:

The Three color bands inductor as Red, Brown & Gold:

Red = 2, Brown = 1 & Gold = 0.1 i.e.

  • = 21 x 0.1 = 2.1 µH

Mostly, the three color band inductors have a tolerance of ±20%. This way, the value of the inductor is 2.1 µH – ±20%.

3 Band Inductor Color Code

The following table shows the three bands inductor color codes and its values.

Band Color 1st Digit 2nd Digit Multiplier
BLACK 0 0 1
BROWN 1 1 10
RED 2 2 100
ORANGE 3 3 1,000
YELLOW 4 4 10,000
GREEN 5 5 100,000
BLUE 6 6 1,000,000
VIOLET 7 7
GREY 8 8
WHITE 9 9
GOLD 0.1
SILVER 0.01

3-Bands Inductor Color Code Calculator

First Digit Second Digit Multiplier
Inductance:

Reading 4 Bands Inductor Color Codes

If there are four color bands printed on an inductor, it means

  • 1st Color Band = First Number of Value of Inductor.
  • 2nd Color Band = Second Number of value of Inductor.
  • 33rd Color Band = The number of Zeros (as multiplier) with the first two digits of Inductor (In numbers).
  • 4th Color Band = Tolerance in percentage.
Example:

The Four color bands inductor as Green, Blue, Brown & Gold:

Green = 5, Blue = 6, Brown = 100 & Gold = ±5% i.e.

  • = 56 x 102 = 56 mH

The fourth band as Golden color shows the tolerance of ±5%. Therefore, the value of the inductor is 56 mH – ±5%.

4 Band Inductor Color Code

The following table shows the four bands inductor color codes and its values.

Band Color 1st Digit 2nd Digit Multiplier Tolerance (%)
BLACK 0 0 1 ± 20%
BROWN 1 1 10 ± 1%
RED 2 2 100 ± 2%
ORANGE 3 3 1,000 ± 3%
YELLOW 4 4 10,000 ± 4%
GREEN 5 5 100,000
BLUE 6 6 1,000,000
VIOLET 7 7
GREY 8 8
WHITE 9 9
GOLD 0.1 ± 5%
SILVER 0.01 ± 10%

4-Bands Inductor Color Code Calculator

First Digit Second Digit Multiplier Tolerance
Inductance:
Tolerance:

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Reading 5 Bands Inductor Color Codes

If there are five color bands printed on an cylindrical molded inductor, it means

  • 1st Color Band = Mil-Spec (Military Specification) Identifier – Always Double-Width Silver Band / Strip which identifies the military radio-frequency inductors.
  • 2nd Color Band = First Number of Value of Inductor.
  • 33rd Color Band = Second Number of value of Inductor.
  • 4th Color Band = The number of Zeros (as multiplier) with the first two digits of Inductor (In numbers).
  • 5th Color Band = Tolerance in percentage.
Example:

The Five color bands inductor as Silver , Red, Blue, Brown & Gold:

Silver = Mil-Spec, Red = 2, Blue = 6, Brown = 10, & Gold = ±5% i.e.

  • = 26 x 10 = 260 µH

The fifth band as Golden color shows the tolerance of ±5%. Therefore, the value of the inductor is 260 µH – ±5%.

5 Band Inductor Color Code

The following table shows the four bands inductor color codes and its values.

Band No =➤ 1st Band 2nd Band 3rd Band 4th Band 5th Band
Band Color Mil-Spec*1 1st Digit 2nd Digit Multiplier Tolerance (%)
BLACK       0 0 1 ± 20%
BROWN       1 1 10 ± 1%
RED       2 2 100 ± 2%
ORANGE       3 3 1,000 ± 3%
YELLOW       4 4 10,000 ± 4%
GREEN       5 5 100,000
BLUE       6 6 1,000,000
VIOLET       7 7
GREY       8 8
WHITE       9 9
GOLD       . *2 . *2 0.1 ± 5%
SILVER       0.01 ± 10%
  • *1 Mil-Spec (Military Specification) Identifier – Always Double-Width Silver Band / Strip.
  • *2 Decimal Points (.) instead of significant figures.

5-Bands Inductor Color Code Calculator

MIL Spec First Digit Second Digit Multiplier Tolerance
Inductance:
Tolerance:

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Inductance Value Code to Inductor Color Codes Calculator

The following calculator will convert the value of inductance printed in code on an inductor to the four bands of inductor color codes. This calculator supports 4-colored strips and values of inductances in H (Henries), mH (milli-henries) and µH (micro-henries). Just put the code of the inductor in digits e.g. 100, 102, 233 etc and click on calculate for the desired color codes. 

Enter Values
Enter Inductor Code:
Tolerance %:
            
The Color Code is:


Reading Chip & SMD (Surface Mount Device) Inductor Color Codes 

On SMD inductors, there is no possibility to print the inducting marking or color code bands due to the small surface area of the tiny component. This way, only colored dots are printed on these inductors to represent the value of inductance in nanohenries. Keep in mind that these dots do not represent the polarity of the inductors and can only be used in clockwise direction to determine the value of SMD inductors.

Reading SMD Inductor Color Dots

For Example:

The colored dots in clockwise direction on an SMD inductor are Yellow, Blue & Red. This way:

  • Yellow = 4
  • Blue = 6
  • Red = 102

Hence the value of the SMD inductor is 4600 nH.

Reading RF (Radio Frequency) Inductor Color Dots Codes 

Radio frequency or RF inductors are the same like SMD and chip inductors in size. The marking method is the same as the above one i.e. if there is only one color dot, it shows the inductance and other specifications can be seen in the related datasheet.

On the other hand, if there are three colored dots printed on the RF inductors, the first two opposite colored dots (in clockwise direction) show the first and second digit (significant figures) respectively while the single dot on the other end represents the multiplier.

Good to know: The single or three dots are not supposed to represent the polarity of the inductor but only the value of inductance in nanohenries (nH).

Reading RF Inductor Color Dots Coding

For Example:

The colored dots in clockwise direction on an RF inductor are RED, RED & Gold. This way:

  • Red = 2
  • Red = 2
  • Gold = 0.1

Hence the value of the RF inductor is 2.2 nH.

The following table shows the 1008 and Midi Spring Series Inductor 3 – Color Dots Codes and its values of inductances in nH.

Series Color Dots Codes Inductance Value Sub-Series
1008CT Series ⚫ 🟡 ⚫ 4.7 nH 1008CT-040X_LC
⚫ ⚪ ⚫ 8.2 nH 1008CT-080X_LC
1008HT Series ⚫ 🔴 ⚫ 3.3 nH 1008HT-3N3T_LC
⚫ 🔵 ⚫ 6.8 nH 1008HT-6N8T_LC
⚫ 🟣 ⚫ 7.2 nH 1008HT-7N2T_LC
1008HQ Series ⚫ 🔴 ⚫ 3.0 nH 1008HQ-3N0T_LC
⚫ 🟡 ⚫ 4.1 nH 1008HQ-4N1T_LC
⚫ 🟣 ⚫ 7.8 nH 1008HQ-7N8T_LC
1206CS Series ⚫ 🔴 ⚫ 3.3 nH 1206CS-030T_LC
⚫ 🔵 ⚫ 6.8 nH 1206CS-060T_LC

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Standard Inductor Values of Inductance

Following is the table of most common used and available inductors both in µH (microhenries) and nH (nanohenries).

Standard Inductor Values of Inductance
µH & nH µH & nH µH & nH µH & nH
1.0 10 100 1000
1.1 11 110 1100
1.2 12 120 1200
1.3 13 130 1300
1.5 15 150 1500
1.6 16 160 1600
1.8 18 180 1800
2.0 20 200 2000
2.2 22 220 2200
2.4 24 240 2400
2.7 27 270 2700
3.0 30 300 3000
3.3 33 330 3300
3.6 36 360 3600
3.9 39 390 3900
4.3 43 430 4300
4.7 47 470 4700
5.1 51 510 5100
5.6 56 560 5600
6.2 62 620 6200
6.8 68 680 6800
7.5 75 750 7500
8.2 82 820 8200
8.7 87 870 8700
9.1 91 910 9100

Charts & Tables in image format:

Standard Inductor Values of Inductance
Standard Inductor Values of Inductance

Tolerance of Inductors

Inductance Values Abbreviation
Inductance Values Abbreviation
1008 & Midi Spring Series Inductor 3 - Color Dots Codes
1008 & Midi Spring Series Inductor 3 – Color Dots Codes

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2 Comments

  1. Hi, your diagram and text for the 4 band color code for inductors is incorrect. You show a 4 color with Green, Blue, Red, and Gold as being 56×10^2 = 560uH when it should be 56×10^2 = 5.6mH. The embedded calculator works correctly, it was only the text of the article that was wrong.

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