About the Resistor Color Code Calculator
What is the Resistor Color Code Calculator?
Through-hole resistors are marked with coloured bands instead of printed values. This resistor colour code calculator decodes them.
In a 4-band resistor, the first two bands are digits, the third is the multiplier and the fourth is tolerance. A 5-band resistor adds a third digit for higher precision.
How to use the Resistor Color Code Calculator
- Number of Bands (sample: 4 bands)
- 1st Band (digit) (sample: Yellow (4))
- 2nd Band (digit) (sample: Violet (7))
- 3rd Band (digit, 5-band only) (sample: Black (0))
- Multiplier Band (sample: Red (×100))
- Tolerance Band (sample: Gold (±5%))
- Press Decode Resistor (results also refresh as you type). The result card shows the Resistance, along with Value in ohms, Minimum and Maximum.
Formula used
Resistance = (digits) × multiplier, ± tolerance
- Digits = black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9
- Tolerance = brown ±1%, red ±2%, gold ±5%, silver ±10%
Read from the end with bands closest together; the tolerance band is often set apart.
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Number of Bands | 4 bands |
| 1st Band (digit) | Yellow (4) |
| 2nd Band (digit) | Violet (7) |
| 3rd Band (digit, 5-band only) | Black (0) |
| Multiplier Band | Red (×100) |
| Tolerance Band | Gold (±5%) |
| Result | Value |
|---|---|
| Resistance | 4.7 kΩ ±5% |
| Value in ohms | 4,700 Ω |
| Minimum | 4.465 kΩ |
| Maximum | 4.935 kΩ |
Tips for using the Resistor Color Code Calculator
- A memory aid: "BB ROY of Great Britain had a Very Good Wife" (black, brown, red, orange, yellow, green, blue, violet, grey, white).
- Confirm with a multimeter if colours are faded.