explainer
How to Read SMD Resistor Codes (103, 4700, 01C and R47)
By the LazyTools team · Published 2026-07-12 · Updated 2026-07-12 · 4 min read
A surface-mount resistor is too small for color bands, so it prints a short number instead — and 103, 4700, 01C and R47 are all valid ways to write a resistance. The rules aren’t intuitive, and the most common mistake (reading 470 as 470 Ω when it means 47 Ω) can quietly break a circuit. Here’s how each format works.
The 3-digit code (the common one)
Most chip resistors carry a 3-digit code that works exactly like the old resistor color bands: the first two digits are significant figures, and the third is the number of zeros to add (a ×10ⁿ multiplier). The result is in ohms.
103→10+ 3 zeros = 10,000 Ω = 10 kΩ472→47+ 2 zeros = 4,700 Ω = 4.7 kΩ220→22+ 0 zeros = 22 Ω
That last one is the trap. 470 is not 470 Ω — it’s 47 with zero extra zeros = 47 Ω. If you actually want 470 Ω, the code is 471 (47 × 10¹). When a value looks “off by a decade,” this is almost always why.
The 4-digit code (1% parts)
Precision 1% resistors need more resolution than two figures allow, so they use a 4-digit code: the first three digits are significant figures and the fourth is the zero-count.
1002→100+ 2 zeros = 10 kΩ4700→470+ 0 zeros = 470 Ω1000→100+ 0 zeros = 100 Ω
Same idea as the 3-digit code, one more figure of precision.
R-notation for small values
For resistances below 10 Ω, zeros-and-multipliers don’t help, so the code uses an R in place of the decimal point:
R47= 0.47 Ω4R7= 4.7 Ω47R0= 47 Ω
Wherever you see the R, put a decimal point and read the digits straight off.
EIA-96: two digits and a letter
The tiniest 1% resistors use the compact EIA-96 code: two digits + one letter. The two digits aren’t the value — they’re a position (01–96) in the standard E96 1% value table, and the letter is a power-of-ten multiplier.
| Code digits → value | Letter → multiplier | ||
|---|---|---|---|
01 = 100 | 30 = 200 | A = ×1 | D = ×1000 |
47 = 301 | 68 = 499 | B = ×10 | E = ×10000 |
96 = 976 | … | C = ×100 | R = ×0.01 |
So 01C = 100 × 100 = 10 kΩ, and 68X = 499 × 0.1 = 49.9 Ω (X = ×0.1). The SMD resistor code calculator has the full table built in — type the code and it detects the format for you.
The zero-ohm jumper
A code of 0, 00 or 000 isn’t a resistance at all — it’s a zero-ohm resistor, a wire link in resistor form. Boards use them to hop one track over another, or to leave a spot where a real value can be fitted later.
Reading it without the arithmetic
The formats overlap enough to be genuinely confusing at a glance, so the SMD resistor code calculator decodes any of them and tells you which format it recognised — all in your browser, nothing uploaded. For through-hole parts with colored stripes instead, use the resistor color code calculator; and if those resistors are feeding a tuned circuit, the LC resonant frequency calculator covers the L–C side.
The SMD codes here follow the standard IEC/EIA marking conventions, including the E96 value table used by EIA-96. Values are decoded exactly in your browser. This is general reference information; always confirm a critical value against the manufacturer’s datasheet or by measurement.
Frequently asked questions
What does 103 mean on a resistor?
10 kΩ. In a 3-digit SMD code the first two digits are significant figures and the third is the number of zeros, so 103 is 10 followed by three zeros = 10,000 Ω. Likewise 104 = 100 kΩ and 102 = 1 kΩ.
Why is 470 equal to 47 ohms and not 470?
Because the last digit is a multiplier (a count of zeros), not a value digit. 470 = 47 × 10⁰ = 47 Ω. To mark 470 Ω you'd print 471 (47 × 10¹). Misreading this is the single most common SMD-code mistake.
How do I read a 4-digit SMD resistor code?
Used on precise 1% resistors, it's three significant figures plus a multiplier: 1002 = 100 × 10² = 10 kΩ, and 4700 = 470 × 10⁰ = 470 Ω. The extra digit gives the finer resolution 1% parts need.
What does an R in a resistor code mean?
The R stands in for a decimal point, used for values below 10 Ω (and some precise parts). R47 = 0.47 Ω, 4R7 = 4.7 Ω, 47R0 = 47 Ω.
What is the EIA-96 code on very small resistors?
A compact 1% marking of two digits plus a letter. The two digits are a position in the standard E96 value table (01 = 100, 68 = 499…) and the letter is a power-of-ten multiplier (A = ×1, B = ×10, C = ×100, R = ×0.01, and so on). So 01C = 100 × 100 = 10 kΩ and 68X = 499 × 0.1 = 49.9 Ω.
What is a 000 or 0 resistor for?
It's a zero-ohm resistor — a wire link in the same package as a resistor, used as a jumper to route a track over others, or as a place to fit a real value later. It has essentially no resistance.
How do I tell an EIA-96 code from R-notation?
If the letter is anything other than an R sitting between digits, it's EIA-96 (the leading two digits are a lookup index). An R placed where a decimal point belongs — R47, 4R7 — is R-notation, and the digits are the value directly.