Unlike through-hole resistors with color bands, SMD (Surface Mount Device) resistors use printed numerical or alphanumeric codes to indicate their resistance value. As components get smaller (like 0201 or 01005 packages), reading these codes becomes more challenging, making an SMD Resistor Code Calculator an essential tool for engineers and hobbyists.

Common SMD Resistor Code Systems

Our calculator supports the three most industry-standard marking systems:

1. 3-Digit System (5% Tolerance)

This system is used for standard-tolerance resistors (typically E24 series).

• First 2 digits: Significant figures.

• 3rd digit: Multiplier (number of zeros).

• R as Decimal: If the letter “R” is present, it acts as a decimal point.

Example: 472 = $47 times 10^2 = 4,700Omega$ (4.7 kΩ).

Example: 4R7 = 4.7 Ω.

2. 4-Digit System (1% High Precision)

Used for precision resistors (typically E96 series), providing an extra digit for accuracy.

• First 3 digits: Significant figures.

• 4th digit: Multiplier.

Example: 1001 = $100 times 10^1 = 1,000Omega$ (1 kΩ).

3. EIA-96 System (The “Special” Code)

Found on 1% precision 0603-sized resistors. It uses a two-digit lookup table and a letter multiplier because the component is too small for four digits.

• Digits (01-96): Represent a specific value (e.g., 01 = 100, 88 = 806).

• Letter: Represents the multiplier (e.g., A = 1, B = 10, X = 0.1).

Example: 01A = $100 times 1 = 100Omega$.