SMD Resistor Code Calculator
SMD resistor marking → resistance, auto-detecting 3-digit / 4-digit / R notation / EIA-96.
What it does: Translate the code printed on top of an SMD resistor into a resistance.
When to use it: When you can't read an SMD resistor, checking a BOM, or confirming a placement part number.
MEANS This SMD resistor is — (—).
No history yet. Each calculation is automatically saved to this device.
How to use the SMD resistor decoder
Enter the code, it auto-detects.
- 01
Read the marking
Read the few characters printed on top of the SMD resistor, e.g.
472,4R7,01C. - 02
Type it in directly
The tool auto-detects all four formats — 3-digit / 4-digit / R notation / EIA-96 — no manual selection needed.
- 03
Read the resistance
Get the resistance and which code it uses; EIA-96 is automatically marked ±1%.
Four SMD codes at a glance
The same resistor may use different codes — identify the format before reading.
| Format | Example | Meaning |
|---|---|---|
| 3-digit code | 472 | 47 × 10² = 4.7 kΩ |
| 4-digit code (1%) | 4702 | 470 × 10² = 47 kΩ |
| R notation | 4R7 / R47 | R is the decimal point → 4.7Ω / 0.47Ω |
| EIA-96 (1%) | 01C | value table[01]=100 × C(×100) = 10 kΩ |
| 0 / 000 | 0 | 0Ω jumper (not "no resistor") |
3/4-digit codes: significant digits + multiplier; EIA-96 reuses the E96 standard value table + a multiplier letter.
Common questions, answered in 3 minutes
What does "4R7" mean?
R takes the place of the decimal point, meaning 4.7Ω. Likewise R47 = 0.47Ω, 0R5 = 0.5Ω. Small values are often marked this way because they can't be expressed with a multiplier.
How do I remember the EIA-96 letters?
A=×1, B=×10, C=×100, D=×1000, E=×10⁴, F=×10⁵; for small values use Y/R=×0.01, X/S=×0.1, Z=×0.001. The two digits index into the E96 value table.
Is "000" or "0" a defective part?
No. That's a 0Ω jumper resistor, used specifically to bridge traces — its resistance is just 0Ω.
How do 3- and 4-digit codes differ in precision?
A 4-digit code has one extra significant digit and is generally a ±1% precision resistor; 3-digit codes are mostly ±5%. But the actual tolerance is whatever the package / marking states.
Standards and sources referenced by this tool
| Item | Value / Formula | Source |
|---|---|---|
| EIA-96 value table | E96 (100…976) | IEC 60063 / EIA-96 |
| Multiplier | 3-digit: 3rd char / 4-digit: 4th char / EIA-96: letter | EIA SMD marking |
Coding rules from EIA SMD marking + the E96 standard value table, no external API.