Decode 4-band and 5-band resistor color codes into resistance and tolerance, plus a series/parallel resistance calculator.
Select the color bands and click Calculate
This free resistor calculator decodes the colored bands printed on a resistor into its actual resistance value and tolerance range, supporting both common 4-band and more precise 5-band resistors. It also includes a series and parallel resistance calculator for combining multiple resistors into one equivalent value.
Select 4-band or 5-band to match your physical resistor, then choose each band's color from left to right as printed on the component. The first two (or three, for 5-band) bands represent significant digits, the next band is a multiplier (a power of ten to scale those digits by), and the final band shows the tolerance — how far the actual resistance may vary from the stated value. The calculator combines these into a resistance value in ohms, plus a minimum and maximum range based on the tolerance.
Electronics hobbyists and students who need to quickly identify an unmarked or hard-to-read resistor, and anyone designing a circuit who needs to combine multiple resistors into a target resistance value using series or parallel combinations.
The decoding logic and series/parallel formulas this calculator uses
Each color from Black (0) through White (9) represents one significant digit, read left to right as printed on the resistor body.
The multiplier band scales the significant digits by a power of ten (or 0.1/0.01 for Gold/Silver), placing the decimal point correctly.
Resistors in series simply add together, while resistors in parallel combine via reciprocals, always producing a total lower than the smallest individual resistor.
From selecting bands to reading the resistance value
Select the number of color bands printed on your resistor.
Match the colors on your physical resistor to the dropdowns, reading left to right.
See the decoded resistance value, tolerance, and minimum/maximum range instantly.
Enter multiple resistor values to find their combined series and parallel resistance.
Decoding a common 4-band resistor, then combining resistors in parallel
Standard IEC 60062 color values used by this calculator
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | — |
| Yellow | 4 | ×10,000 | — |
| Green | 5 | ×100,000 | ±0.5% |
| Blue | 6 | ×1,000,000 | ±0.25% |
| Violet | 7 | ×10,000,000 | ±0.1% |
| Gray | 8 | ×100,000,000 | ±0.05% |
| White | 9 | ×1,000,000,000 | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
| No band | — | — | ±20% |
Where decoding or combining resistors comes up
Decode a resistor's value from its color bands without needing a multimeter handy.
Sort through a parts bin and confirm resistor values before building a circuit.
Practice reading resistor color codes for class assignments and lab work.
Combine standard resistors in series or parallel to hit a non-standard target value.
Double-check a resistor's tolerance range before using it in a precision circuit.
What this resistor calculator does well, and where it has boundaries
Read resistor color codes accurately
Summary: This resistor calculator decodes 4-band and 5-band resistor color codes into resistance and tolerance, plus combines multiple resistors in series or parallel — free, instant, and following the standard IEC 60062 color code. Pair it with the Ohm's Law Calculator or Voltage Drop Calculator for related circuit work.
Common questions about resistor color codes and combinations
Standards references to complement this calculator
Other circuits and measurement tools