How to use the resistor calculator
- Color code → value: pick 4, 5 or 6 bands and choose each band’s color from left to right. Hold the resistor with the tolerance band — usually gold, silver or brown, often a little apart from the others — on the right.
- Value → color code: enter a value such as 4.7 kΩ to see its 4-band (±5%) and 5-band (±1%) codes, drawn as bands.
- Series and parallel: type up to ten values, such as 100, 220, 470 or 4k7 10k 1M, to get both the series and the parallel total at once.
Every value also shows the nearest standard values of the E12, E24 and E96 series, which is what you can actually buy.
Resistor color code chart
| Color | Digit | Multiplier | Tolerance | Temp. coefficient |
|---|---|---|---|---|
| Black | 0 | ×1 | — | 250 ppm/K |
| 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% | 20 ppm/K |
| Blue | 6 | ×1,000,000 | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10,000,000 | ±0.1% | 5 ppm/K |
| Gray | 8 | ×100,000,000 | ±0.05% | 1 ppm/K |
| White | 9 | ×1,000,000,000 | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
| No band | — | — | ±20% | — |
The colors follow the international standard IEC 60062. A 4-band resistor has two digit bands, a 5- or 6-band resistor three; then come the multiplier and the tolerance, and on a 6-band resistor the temperature coefficient last. The classic memory aid is “Big Boys Race Our Young Girls, But Violet Generally Wins” for black to white.
Worked examples
- Brown – black – red – gold: 1, 0, × 100 = 1,000 Ω = 1 kΩ ±5%, so anything from 950 Ω to 1,050 Ω is within tolerance.
- Yellow – violet – green – brown – brown: 4, 7, 5, × 10 = 4,750 Ω = 4.75 kΩ ±1%, a value of the E96 series.
- Red – red – gold – gold: 2, 2, × 0.1 = 2.2 Ω ±5%. A gold multiplier means the value is below 10 Ω.
Series and parallel resistors
In series the same current flows through every resistor and the resistances add: R = R1 + R2 + … In parallel every resistor has the same voltage and the conductances add: 1/R = 1/R1 + 1/R2 + … For two resistors that is R = R1 × R2 ÷ (R1 + R2), so 100 Ω ∥ 100 Ω = 50 Ω, and n equal resistors in parallel give R ÷ n. For 100 Ω, 220 Ω and 470 Ω the series total is 790 Ω and the parallel total 60.0 Ω. The table under the result shows how the voltage divides in series (in proportion to each resistance) and how the current divides in parallel (in inverse proportion), which is handy for voltage dividers and for sharing power between resistors.
Standard values: E12, E24 and E96
Resistors are made in preferred values (IEC 60063) spaced so that neighboring values overlap at their tolerance: 12 values per decade for ±10% (E12: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82), 24 for ±5% (E24) and 96 for ±1% (E96). If your design calls for 5 kΩ, the nearest E24 part is 5.1 kΩ and the nearest E96 part 4.99 kΩ; to check what the resistor does in a circuit, use the Ohm’s law calculator.
Before relying on colors, measure: faded or heat-darkened bands are easy to misread (red, orange and brown look alike), and an ohmmeter settles it in seconds — out of circuit, because other parts in parallel change the reading. Surface-mount resistors carry a printed number code instead of color bands.
Frequently asked questions
How do you read a resistor color code?
Turn the resistor so the tolerance band (gold, silver or brown, often spaced apart) is on the right. Read the digit bands from the left, then multiply by the multiplier band: brown-black-red-gold is 1, 0, × 100 = 1,000 Ω ±5%.
How do I calculate resistors in parallel?
Add the reciprocals and take the reciprocal of the sum: 1/R = 1/R₁ + 1/R₂ + … For two resistors, R = R₁ × R₂ ÷ (R₁ + R₂). Two 100 Ω resistors in parallel make 50 Ω.
What is the difference between 4-band and 5-band resistors?
A 4-band resistor has two significant digits and is usually ±5% (gold); a 5-band resistor has three digits and is usually a ±1% precision part (brown). A 6th band gives the temperature coefficient in ppm/K.
What color code is 10k?
10 kΩ is brown-black-orange with a gold band for ±5% (1, 0, × 1,000), or brown-black-black-red-brown on a 5-band ±1% resistor (1, 0, 0, × 100).
Which way do you read a resistor?
From the end with the bands closest to the edge, with the tolerance band last. If both ends look alike, try both directions: usually only one gives a standard E-series value.
Last updated: October 19, 2026