Calculator
Use decode mode to read an existing SMD marking. Use encode mode to generate compatible markings from a resistance value.
Plotly Graph and Calculation History
The chart compares decoded or encoded resistance values on a logarithmic scale for easier decade-level viewing.
| # | Mode | Input | Detected / Target | Resistance | Engineering Format | Formula |
|---|---|---|---|---|---|---|
| No history available. | ||||||
Example Data Table
These examples help verify common SMD resistor markings before testing a live component.
| Code | Type | Working Rule | Resistance | Engineering Format |
|---|---|---|---|---|
| 000 | Zero Ohm | Jumper marking | 0 Ω | 0 Ω |
| R47 | R Marking | Replace R with decimal point | 0.47 Ω | 0.47 Ω |
| 330 | 3-Digit | 33 × 100 | 33 Ω | 33 Ω |
| 472 | 3-Digit | 47 × 102 | 4700 Ω | 4.7 kΩ |
| 1002 | 4-Digit | 100 × 102 | 10000 Ω | 10 kΩ |
| 01A | EIA-96 | 100 × 1 | 100 Ω | 100 Ω |
| 07B | EIA-96 | 115 × 10 | 1150 Ω | 1.15 kΩ |
| 96C | EIA-96 | 976 × 100 | 97600 Ω | 97.6 kΩ |
Formula Used
1) 3-Digit Numeric Marking
Formula: Resistance = (first two digits) × 10last digit Ω
Example: 472 = 47 × 102 = 4700 Ω
2) 4-Digit Numeric Marking
Formula: Resistance = (first three digits) × 10last digit Ω
Example: 1002 = 100 × 102 = 10000 Ω
3) R Decimal Marking
Rule: Replace the letter R with the decimal point.
Example: 4R7 = 4.7 Ω, R22 = 0.22 Ω
4) EIA-96 Marking
Formula: Resistance = EIA-96 base value × letter multiplier
Example: 07B = 115 × 10 = 1150 Ω
5) Zero Ohm Marking
Rule: Codes like 0, 00, 000, and 0000 indicate a jumper-style near-zero resistance part.
How to Use This Calculator
- Choose Decode SMD Code to read an existing resistor marking, or choose Encode Resistance to generate matching code styles.
- For decoding, enter the printed code such as 472, 1002, 4R7, 000, or 07B.
- For encoding, enter the resistance value and select the correct unit.
- Set Interpret As to Auto Detect for convenience, or manually force the intended format.
- Use the EIA-96 matching option to require an exact code or allow the nearest available precision code.
- Click Calculate to display the result above the form, then review compatible encodings, formula details, and graph history.
- Download the current result as CSV or PDF, or export the full history table as CSV.
FAQs
1) What code types does this calculator support?
It supports 3-digit numeric, 4-digit numeric, R-marked decimal, zero-ohm jumper, and EIA-96 resistor markings. Auto detection handles most common codes, while manual selection helps when you already know the code family.
2) Can it decode zero-ohm jumper markings?
Yes. Inputs such as 0, 00, 000, and 0000 are treated as zero-ohm jumpers. The result area identifies them separately so they are not confused with ordinary resistor values.
3) What does the letter R mean in SMD codes?
The letter R acts as a decimal point. For example, 4R7 means 4.7 ohms and R22 means 0.22 ohms. This notation is common for lower resistance values.
4) Does the marking always reveal tolerance?
Not always. Many markings show only resistance. EIA-96 markings are commonly associated with precision parts, but the final tolerance still depends on the exact component series and manufacturer data.
5) Why does the calculator show equivalent encodings?
Equivalent encodings help you compare how the same resistance may appear in different marking systems. This is useful when cross-checking a PCB, bill of materials, repair notes, or replacement stock.
6) Why might a 3-digit code be unavailable in encode mode?
A 3-digit numeric code needs an exact two-significant-digit representation and a valid multiplier. Some resistance values cannot be represented exactly in that shorter numeric format, so the calculator leaves it blank.
7) What does nearest EIA-96 match mean?
Nearest EIA-96 match finds the closest standard EIA-96 coded value when an exact code does not exist. The result includes the suggested code and the percentage difference from your requested resistance.
8) Can I keep multiple calculations for comparison?
Yes. Each calculation is stored in the on-page history table and plotted on the chart. You can export the history as CSV or clear it whenever you want a fresh comparison set.