4-band resistor: yellow, violet, red, gold
Input
Yellow · Violet · Red · GoldOutput
4,700 Ω (4.7 kΩ) ±5%Digits 4 and 7 form 47. Red multiplies by 100. Gold is ±5%. The nominal range is 4,465–4,935 Ω.
Resistor Calculator
Tap 4, 5, or 6 color bands on a live resistor diagram. Read the nominal value, tolerance range, and nearest E24 or E96 value, or calculate series, parallel, and wire resistance.
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By Muhammad Abdullah Rauf · Founder, EverydayTools.proUpdated 2026-10-23
How do you calculate a resistor's value from its color bands?
Resistor color codes indicate nominal resistance and tolerance. Four-band resistors contain two digits, a multiplier, and tolerance. Five-band resistors use three digits; six-band resistors add a temperature-coefficient band. Select the correct number of bands and read from the end where the digit bands start. This tool also calculates total resistance of series or parallel networks and estimates conductor resistance from material, length, and cross-sectional area.
Resistor color code, series and parallel formulas
Nominal values are decoded from standard color-band digits and multipliers. Tolerance defines the manufacturing resistance range, not an exact measurement. Series/parallel results assume ideal, linear, passive resistors. DC conductor estimates use reference resistivity at about 20°C.
Formula
Color code: R = significant digits × multiplier
Tolerance range: Rmin = R × (1 − tolerance%/100); Rmax = R × (1 + tolerance%/100)
Series: Rtotal = R1 + R2 + …
Parallel: 1/Rtotal = 1/R1 + 1/R2 + …
Conductor: R = ρ × L / A, where A is in square metersAssumptions
- Color bands follow conventional resistor color-code conventions.
- Series and parallel networks are ideal passive DC resistance networks.
- Copper resistivity approximated as 1.724 × 10⁻⁸ Ω·m; aluminum 2.82 × 10⁻⁸ Ω·m near 20°C.
- Conductor mode uses single-path length; outgoing and return lengths are different.
Limitations
- Nearest E24 and E96 values are IEC preferred numbers, not a stock check at a supplier.
- Six-band temperature coefficient does not automatically adjust resistance for temperature.
- Not a substitute for bench measurement, material certificates, SMD codes, or conductor ampacity.
How to use the resistor calculator
Choose 4, 5, or 6 bands
Match the number of color bands on the resistor body.
Tap each band color
Start at the first digit band and continue through the multiplier, tolerance, and optional temperature band.
Read ohms, tolerance, and the E-series value
The result shows the nominal resistance, the tolerance range, and the nearest IEC E24 and E96 preferred numbers.
Switch to series, parallel, or wire resistance
Enter positive resistor values, or copper or aluminum length and area, when you need those calculations.
Resistor color code and resistance examples
4-band resistor: red, red, brown, gold
Input
Red · Red · Brown · GoldOutput
220 Ω ±5%22 × 10 = 220 Ω. The range at ±5% is 209–231 Ω.
5-band resistor: brown, black, black, red, brown
Input
Brown · Black · Black · Red · BrownOutput
10 kΩ ±1%Three significant digits give 100. Red multiplies by 100. Brown means ±1%, or 9.9–10.1 kΩ.
Two resistors in series
Input
100 Ω and 220 ΩOutput
320 ΩSeries resistances add: 100 + 220 = 320 Ω.
Two resistors in parallel
Input
100 Ω and 220 ΩOutput
68.75 ΩR = (100 × 220) ÷ (100 + 220) = 68.75 Ω.
Copper wire at 20°C
Input
10 m one-way length, 2.5 mm² copperOutput
0.06896 Ω approximatelyR = ρL/A = (1.724 × 10⁻⁸ Ω·m × 10 m) ÷ (2.5 × 10⁻⁶ m²). Real conductors vary with temperature and specification.
Resistor color bands and their meaning
Each position has a distinct role; the same color does not mean the same thing in every band.
| Bands | Digits | Multiplier | Tolerance | Temperature coefficient |
|---|---|---|---|---|
| 4 | First 2 | Third | Fourth | — |
| 5 | First 3 | Fourth | Fifth | — |
| 6 | First 3 | Fourth | Fifth | Sixth |
Resistor color code chart
Digit, multiplier, tolerance, and temperature-coefficient meanings used by this calculator.
| Color | Digit | Multiplier | Tolerance | ppm/K |
|---|---|---|---|---|
| Black | 0 | ×1 | — | 250 |
| Brown | 1 | ×10 | ±1% | 100 |
| Red | 2 | ×100 | ±2% | 50 |
| Orange | 3 | ×1,000 | — | 15 |
| Yellow | 4 | ×10,000 | — | 25 |
| Green | 5 | ×100,000 | ±0.5% | 20 |
| Blue | 6 | ×1,000,000 | ±0.25% | 10 |
| Violet | 7 | ×10,000,000 | ±0.1% | 5 |
| Gray | 8 | ×100,000,000 | ±0.05% | 1 |
| White | 9 | ×1,000,000,000 | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
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Frequently Asked Questions
What is the color code for a 4.7k ohm resistor?
A common 4-band 4.7 kΩ ±5% resistor has yellow, violet, red, and gold bands. 47 × 100 = 4,700 Ω; gold indicates ±5%.
What is the color code for a 220 ohm resistor?
A typical 4-band 220 Ω ±5% resistor is red, red, brown, gold. The digits are 22 and the multiplier is 10.
What is the color code for a 10k resistor?
For 4 bands at ±5%, brown, black, orange, gold means 10 × 1,000 = 10,000 Ω. For 5 bands at ±1%, brown, black, black, red, brown also means 10 kΩ.
What is the difference between 4-band, 5-band, and 6-band resistor color codes?
Four-band resistors have two significant digits. Five-band resistors have three. Six-band resistors add a sixth band for temperature coefficient in parts per million per kelvin.
What does a gold resistor band mean?
As a multiplier, gold means ×0.1. In a tolerance position, gold means ±5%. Its role depends on where it appears.
How do you calculate resistors in parallel?
Use 1/Rtotal = 1/R1 + 1/R2 + … . For two resistors, Rtotal = R1 × R2 ÷ (R1 + R2). A parallel total is smaller than the smallest positive branch resistance.
How do you calculate resistors in series?
Add the individual resistance values: Rtotal = R1 + R2 + … . For 100 Ω and 220 Ω, the series result is 320 Ω.
How accurate is the resistor color code calculator?
The nominal value is calculated exactly from the selected color bands. Physical parts vary within the stated tolerance and with temperature, aging, and other factors; measure with a meter when required.
Can I calculate wire resistance?
Yes. Switch to Wire resistance and enter copper or aluminum, one-way length, and cross-sectional area in mm². The estimate uses R = ρL/A near 20°C, not conductor ampacity.
Can this calculator read SMD resistor codes?
No. Surface-mount codes use a printed number or the EIA-96 code. This page decodes axial color bands and then shows the nearest IEC E24 or E96 preferred value for that nominal resistance.
What is the nearest E24 value to 5,000 ohms?
The nearest E24 preferred value to 5,000 Ω is 5.1 kΩ (5,100 Ω), about 2% higher. E96 also includes 4.99 kΩ, which is closer. Preferred numbers are not a promise that a seller stocks that part.
Privacy, accuracy, and trust
Privacy
Inputs and calculations run locally in your browser; no resistor values are uploaded.
Nominal component reference only. Check real components, circuit conditions, wire ampacity, and safety requirements independently.
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Reviewed on 2026-10-23.
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