SMD Resistor Code Decoder
Decode 3-digit, 4-digit and EIA-96 surface-mount resistor codes (472, 4R7, 1002, 68X) to a value, or list every code a value can carry, with E96 built in.
The resistance of a chip resistor from the few characters printed on it, with the marking system identified and the arithmetic shown — or the codes to expect on a part of a given value.
Example: 472 is 47 × 10² = 4.7 kΩ; 4R7 is 4.7 Ω; 1002 is 100 × 10² = 10 kΩ; the EIA-96 code 68X is position 68 (499) × 0.1 = 49.9 Ω.
Three characters,
three different alphabets.
The numeric codes, the EIA-96 letter code, and how to tell them apart on a part too small for colour bands.
Three- and four-digit codes
The last digit is a power of ten and the digits before it are the significant figures: 472 is 47 × 10² = 4,700 Ω, 103 is 10 × 10³ = 10 kΩ. Precision parts use four digits with three significant figures — 1002 is 100 × 10² = 10 kΩ, 4992 is 49.9 kΩ. Values below 10 Ω (or 100 Ω on four-digit parts) put an R where the decimal point goes: 4R7 is 4.7 Ω, R22 is 0.22 Ω, 1R00 is 1.00 Ω. A marking of 0 or 000 is a zero-ohm link used as a jumper.
EIA-96
Small 1 % parts often carry two digits and a letter. The digits are a position, 01 to 96, in the E96 preferred-value series (100, 102, 105 … 953, 976), and the letter is the multiplier: A ×1, B ×10, C ×100, D ×1,000, E ×10,000, F ×100,000, and for sub-ohm and low values X or S ×0.1, Y or R ×0.01, Z ×0.001. So 01C is 100 × 100 = 10 kΩ and 68X is 499 × 0.1 = 49.9 Ω. The E96 values here are computed from the defining formula, which reproduces the IEC 60063 table exactly.
Telling them apart, and what is not covered
Digits only means a numeric code; a trailing letter means EIA-96; an R inside means a decimal point. A three-digit reading that is not a preferred E24 or E96 value is flagged — often the part uses a manufacturer's own code, or a 0 has been read as an O. Some makers use an underline or a different letter set for tolerance, and very small packages (0402 and below) are often unmarked; those need the reel label or a meter. Encoding a value gives each code it can carry, and tells you when a value has no exact code. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- IEC 60062:2016, Marking codes for resistors and capacitors — numeric codes with R as the decimal point
- EIA-96 marking system (Electronic Industries Alliance) — two-digit E96 position plus multiplier letter
- IEC 60063:2015, Preferred number series for resistors and capacitors — E24 and E96
Last reviewed 19 September 2026. How results are checked: How we verify.