SMD Component Identification

SMD Resistor Code Calculator

Decode SMD resistor markings including 3-digit, 4-digit, R-marked decimal and EIA-96 codes. Enter the marking printed on your resistor to calculate its resistance, or enter a resistance value to generate common SMD codes.

Decode an SMD Resistor

Select the marking system and enter the code printed on the component.

Examples: 103, 472, 1001, 4R7, 0R22, 01C, 68X
Resistance
10 kΩ
3-digit numeric code
Code
103
Format
3-digit
Ohms
10,000 Ω
Multiplier
×1,000
SMD Component
103
Decoding
10 × 10³ = 10,000 Ω

Generate an SMD Code

Enter a resistance value to generate common numeric SMD markings.

Ω
3-Digit Code
103
4-Digit Code
1002
R-Marked
10K

SMD Resistor Code Formulas

3-Digit Code

The first two characters are significant digits. The third character is the power-of-ten multiplier.

R = AB × 10ᶜ

Example: 103 = 10 × 10³ = 10 kΩ

4-Digit Code

The first three characters are significant digits. The fourth character is the multiplier.

R = ABC × 10ᴰ

Example: 1001 = 100 × 10¹ = 1 kΩ

R-Marked Code

R is used instead of a decimal point.

4R7 = 4.7 Ω

Other examples include 0R22 = 0.22 Ω and R10 = 0.10 Ω .

How to Read an SMD Resistor Marking

1

Identify the code

Determine whether the marking is a 3-digit, 4-digit, R-marked or EIA-96 code.

2

Separate digits

For numeric codes, separate the significant digits from the final multiplier digit.

3

Apply multiplier

Multiply the significant digits by the appropriate power of ten.

4

Verify value

Check the calculated resistance against the circuit design, datasheet or a multimeter.

Common SMD Resistor Codes

Code Calculation Resistance
100 10 × 10⁰ 10 Ω
220 22 × 10⁰ 22 Ω
330 33 × 10⁰ 33 Ω
472 47 × 10² 4.7 kΩ
103 10 × 10³ 10 kΩ
104 10 × 10⁴ 100 kΩ
105 10 × 10⁵ 1 MΩ
1001 100 × 10¹ 1 kΩ
4702 470 × 10² 47 kΩ
4R7 Decimal marker 4.7 Ω
0R22 Decimal marker 0.22 Ω
R10 Decimal marker 0.10 Ω

EIA-96 SMD Resistor Codes

Precision SMD resistors may use the EIA-96 marking system. Instead of directly encoding the resistance with two or three significant digits, the first two characters identify one of the 96 E96-series values and the final character identifies the multiplier.

First 2 Characters
E96 Index
Final Character
Multiplier
Typical Use
Precision SMD

Example: 01C uses E96 value 100 and multiplier C = ×100, resulting in 10,000 Ω or 10 kΩ.

EIA-96 Multiplier Codes

Code Multiplier Example
Z ×0.001 01Z = 0.1 Ω
Y ×0.01 01Y = 1 Ω
X ×0.1 01X = 10 Ω
A ×1 01A = 100 Ω
B ×10 01B = 1 kΩ
C ×100 01C = 10 kΩ
D ×1,000 01D = 100 kΩ
E ×10,000 01E = 1 MΩ
F ×100,000 01F = 10 MΩ
G ×1,000,000 01G = 100 MΩ

R-Marked Decimal Resistors

4R7

The R replaces the decimal point.

4R7 = 4.7 Ω

0R22

The decimal point appears after the leading zero.

0R22 = 0.22 Ω

R10

An R at the beginning represents a decimal point.

R10 = 0.10 Ω

SMD Resistor Code Applications

PCB Repair

Identify small surface-mount resistors when repairing PCBs, consumer electronics, computers and embedded systems.

Circuit Analysis

Decode resistor values during reverse engineering, troubleshooting and circuit analysis.

PCB Design

Verify component markings and resistance values when selecting or checking SMD resistor components.

Practical Notes

Markings Can Be Tiny

SMD resistors can be extremely small, and some packages do not have enough physical space for a printed marking at all.

Use adequate magnification and lighting when identifying small components. If the marking is unclear, a multimeter and schematic can provide additional evidence.

Check the Component Type

Not every three-character marking is necessarily a standard resistor code. Specialized resistor networks, current-sense components and other devices may use manufacturer-specific markings.

When a result does not agree with the circuit, check the component datasheet or manufacturer documentation.

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SMD Resistor Code FAQ

Most standard SMD resistors use a 3-digit or 4-digit numeric code. In a 3-digit code, the first two digits are significant digits and the third digit is the multiplier. In a 4-digit code, the first three digits are significant digits and the fourth digit is the multiplier.
The letter R is commonly used as a decimal point in SMD resistor markings. For example, 4R7 means 4.7 ohms, 0R22 means 0.22 ohms and R10 means 0.10 ohms.
A 103 marking normally means 10 × 10³ ohms, which is 10,000 ohms or 10 kΩ.
A 472 marking normally means 47 × 10² ohms, which is 4,700 ohms or 4.7 kΩ.
A 1001 marking normally means 100 × 10¹ ohms, which is 1,000 ohms or 1 kΩ.
EIA-96 is a compact 3-character SMD resistor marking system used for precision resistors. The first two characters identify a resistance value from the E96 series and the final character identifies a multiplier.
Three-digit codes generally provide two significant digits plus a multiplier, while four-digit codes provide three significant digits plus a multiplier. Four-digit markings therefore allow more precise nominal resistance values.
Yes. Very small components may have incomplete or difficult-to-read markings, and some special resistor families use proprietary or non-standard codes. When the marking is uncertain, measuring the component and checking its datasheet or circuit context is recommended.