Reading a SMD resistor code

SMD resistors are tidy and are commonly marked with three- or four-digit codes called SMD Resistor Codes that indicate their resistance values.

For a three-digit SMD Resistor Code,

  • the first two numbers indicates the significant digits for the resistance, e.g. “22” indicates 22 ohms
  • the third number will be a multiplier that must be multiplier by the first two numbers, or will indicate how many zeros should be added to the first two numbers. For example, “223” indicates 22 ohms multipled by 10 three times, or with three zeros, for a 22000 or 22k-ohm part.
  • you may see the letter “R”, which calls out a decimal point. For example 1.1 ohms = 1R1 ohm.
  • resistance values below 10 ohms do not have a multiplier.

Here are more examples for three-digit SMD Resistor Codes.

To read the four-digit code, use the same method as the three-digit code. The only difference is the number of significant digits. There are three significant numbers, rather than two, with the last still indicating the multiplier or how many zeros to add to the first three numbers.