Resistor Calculator
Decode resistor color bands, find bands for a given value, or convert SMD codes.
Free & unlimitedWorks offline
Click a band to change its color
Resistance
1.00 kΩ
Tolerance
±5%
Min
950.00 Ω
Max
1.05 kΩ
SMD 3-digit
102
SMD 4-digit
1001
Color code reference
| Color | Digit | Multiplier | Tolerance | TCR |
|---|---|---|---|---|
| Black | 0 | ×1 | — | — |
| Brown | 1 | ×10 | ±1% | 100 ppm/K |
| Red | 2 | ×100 | ±2% | 50 ppm/K |
| Orange | 3 | ×1,000 | — | 15 ppm/K |
| Yellow | 4 | ×10,000 | — | 25 ppm/K |
| Green | 5 | ×100,000 | ±0.5% | — |
| Blue | 6 | ×1,000,000 | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10,000,000 | ±0.1% | 5 ppm/K |
| Grey | 8 | ×100,000,000 | ±0.05% | — |
| White | 9 | ×1,000,000,000 | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
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About this tool
- 1
Select band colors
Click each band position and choose the color from the dropdown. Supports 4-band, 5-band, and 6-band resistors.
- 2
Read the value
The resistance value, tolerance, and temperature coefficient are calculated and displayed instantly.
- 3
Use reverse lookup
Enter a resistance value to see which color band combination represents it.
- The tolerance band (gold or silver) is usually spaced slightly apart from the value bands - orient the resistor so this band is on the right.
- For reverse lookup, the tool shows the nearest standard E-series value if your exact value isn't a standard resistor.
- Use the mnemonic "BB ROY of Great Britain has a Very Good Wife" for the color sequence.
- Visual resistor diagram with selectable color bands
- Supports 4-band, 5-band, and 6-band resistor types
- Reverse lookup: enter a value to find the color code
- Shows nearest standard E12/E24/E96 series values
- Tolerance and temperature coefficient display
- Identifying resistor values while building circuits on a breadboard
- Finding the right color code when selecting resistors from component bins
- Verifying resistor values for PCB assembly or repair work
- Teaching electronics students how to read resistor color codes