Enter a resistance value to find the corresponding SMD code
Calculate power dissipation and check if it's within package limits
Calculate output voltage for voltage divider circuits
Enter multiple SMD codes (one per line) to calculate all values at once
| Letter | Multiplier | Letter | Multiplier |
|---|---|---|---|
| Z | 0.001 | A | 1 |
| Y | 0.01 | B | 10 |
| R | 0.01 | H | 10 |
| X | 0.1 | C | 100 |
| S | 0.1 | D | 1,000 |
| - | - | E | 10,000 |
| - | - | F | 100,000 |
| Package | Dimensions (mm) | Power Rating | Common Use |
|---|---|---|---|
| 0201 | 0.6 × 0.3 | 1/20W (50mW) | Mobile devices |
| 0402 | 1.0 × 0.5 | 1/16W (62.5mW) | Compact electronics |
| 0603 | 1.6 × 0.8 | 1/10W (100mW) | General purpose |
| 0805 | 2.0 × 1.25 | 1/8W (125mW) | Standard applications |
| 1206 | 3.2 × 1.6 | 1/4W (250mW) | Higher power |
| 1210 | 3.2 × 2.5 | 1/2W (500mW) | Power applications |
| 2010 | 5.0 × 2.5 | 3/4W (750mW) | High power |
| 2512 | 6.4 × 3.2 | 1W (1000mW) | Power resistors |
472: 47 × 10² = 4,700Ω = 4.7kΩ
103: 10 × 10³ = 10,000Ω = 10kΩ
2R2: 2.2Ω
R47: 0.47Ω
1502: 150 × 10² = 15,000Ω = 15kΩ
4701: 470 × 10¹ = 4,700Ω = 4.7kΩ
1000: 100 × 10⁰ = 100Ω
51D: 332 × 1,000 = 332kΩ
01C: 100 × 100 = 10kΩ
49Y: 316 × 0.01 = 3.16Ω
| Date | Type | Code | Value | Actions |
|---|---|---|---|---|
| No calculations yet | ||||
Surface-mount resistors carry printed codes rather than colour bands, and there are three systems in circulation. Identifying which one is in use is the whole task.
The first two digits are significant figures and the third is the number of zeros, giving ohms. So 103 is 10 followed by three zeros — 10,000 Ω, or 10 kΩ. A code of 472 is 4,700 Ω.
Three significant figures plus a multiplier. 1002 is 100 followed by two zeros — 10,000 Ω. The extra digit is what allows E96 values such as 4.99 kΩ (4991) to be marked precisely.
On parts too small for four digits, a two-digit number plus a letter is used. The number is a position in the E96 series and the letter is the multiplier — so 01A is 100 Ω and 68C is 49.9 kΩ. This one cannot be decoded by inspection; it needs the lookup table.
4R7 is 4.7 Ω and R22 is 0.22 Ω. This is how sub-ohm values are written without a decimal point that might not print cleanly.When a code is ambiguous between schemes — and three digits can be read as either a 5% three-digit code or a truncated EIA-96 — the package size is the clue, and measuring is faster than guessing.
The first two digits are significant figures and the third is the number of zeros, giving the value in ohms. 103 means 10 kΩ and 472 means 4.7 kΩ.
Three significant figures followed by a multiplier, used on 1% parts. 1002 is 10 kΩ, and the extra digit allows precise E96 values such as 4.99 kΩ (4991).
It marks the decimal point. 4R7 is 4.7 Ω and R22 is 0.22 Ω. It is used because a printed decimal point may not reproduce reliably on a small part.
A zero-ohm link — a wire jumper in resistor form, so that pick-and-place machinery can fit a link without a separate process. Its actual resistance is a few milliohms.
A two-digit number plus a letter used on very small 1% parts. The number is a position in the E96 series and the letter the multiplier, so 01A is 100 Ω. It requires a lookup table rather than direct decoding.
Count the characters and look for a letter. Three digits suggests a 5% part, four digits a 1% part, and two digits plus a letter indicates EIA-96. If it remains ambiguous, measuring is quicker than guessing.