# Resistor Color Code Calculator

Free resistor color code calculator. Set the bands to read the resistance, tolerance and temperature coefficient of 4-band, 5-band and 6-band resistors — or enter a resistance to get its color code.

Read any resistor in seconds. Pick the number of bands and set each color — or flip to **band-color mode** and get the color code for a resistance value you already have. Works for **4-band, 5-band and 6-band** resistors, with tolerance and temperature coefficient.

Resistor

Results

Resistance —

Tolerance —

Temperature coefficient —

Nearest standard value —

Read the bands from the end where they are grouped closest together; the tolerance band (usually gold or silver) sits on its own at the opposite end. Values follow IEC 60062. Tip: click a band on the resistor above to cycle its color.

## Don't just decode resistors — understand the whole circuit

A color-code chart tells you what a resistor *is*. It won't tell you why it's a pull-up, how to size a current-limiting resistor for an LED, or what an RC filter's cutoff frequency should be. **Flux** is the AI design partner that explains circuit architectures to you while you build — and picks real, in-stock parts.

-   Ask "why this resistor value?" and get a real answer
-   Flux explains the circuit as you design it, on the canvas
-   From first breadboard idea to a manufacturable PCB

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### In Flux

Why a 330 Ω resistor (R3) in series with LED1 on the 5 V rail?

![Flux](https://www.flux.ai/p/assets/site/6446c14683b3da60aea75bce_copilot-icon-filled-white.svg)

R3 is LED1's **current-limiting resistor**, not a pull-up — it sets how much current the LED draws so the diode doesn't run away and cook itself.

-   **Rail:** 5 V, and LED1 drops about 2 V forward
-   **Across R3:** 5 V − 2 V = 3 V
-   **Current:** 3 V ÷ 330 Ω ≈ **9 mA**

That's plenty for an indicator and stays well inside the 20 mA the LED and your GPIO can handle. Want it brighter? 220 Ω gives roughly 14 mA — I can swap in an in-stock 0603 part and update the BOM.

## Resistor color code chart

What each color means in each band position (IEC 60062).

| Color | Digit | Multiplier | Tolerance | Temp. coef. (ppm/°C) |
| --- | --- | --- | --- | --- |

## Resistor color code FAQ

### How do you read resistor color codes?

Start from the end where the bands are grouped closest together — the lone band at the opposite end is the tolerance. On a 4-band resistor the first two bands are digits, the third is the power-of-ten multiplier and the fourth is the tolerance. On a 5-band resistor there are three digit bands, then the multiplier and tolerance. A 6-band resistor adds the temperature coefficient in ppm/°C. So yellow-violet-red-gold reads 4, 7, ×100, ±5% = **4.7 kΩ ±5%**.

### What is the 4-band resistor color code?

Two significant digits, a multiplier and a tolerance band. The digit colors run black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8, white 9. The multiplier is the same sequence as powers of ten (black ×1 through white ×10⁹), plus gold ×0.1 and silver ×0.01 for values below 10 Ω. Gold means ±5% tolerance and silver ±10%; no fourth band at all means ±20%.

### What does the 5th band on a resistor mean?

It depends on where it sits. On a 5-band resistor the extra band is a third significant digit, which is how ±1% and ±2% film resistors get the resolution they need (for example brown-black-black-brown-brown = 100 ×10 = 1 kΩ ±1%). If the fifth band is separated from the others near one end, you are looking at a 6-band part and that band is the tolerance, with the last band giving the temperature coefficient.

### What is the temperature coefficient band?

The sixth band gives the resistor's temperature coefficient in parts per million per degree Celsius: brown 100, red 50, orange 15, yellow 25, green 20, blue 10, violet 5 and gray 1 ppm/°C. It tells you how much the resistance drifts as the part heats up — a 100 ppm/°C, 10 kΩ resistor moves about 10 Ω over a 10 °C rise. It matters for precision references and dividers, and not much for pull-ups or LED current limiting.

### Which end of the resistor do I start reading from?

Read away from the tolerance band. On most parts the digit and multiplier bands are grouped toward one end and the tolerance band sits alone, with a wider gap, at the other. If the coloring is ambiguous (for example brown at both ends), measure it: read it both ways and keep the value that lands on a standard E-series number — a real resistor is almost always a standard value.

### What do gold and silver bands mean?

As a tolerance band, gold is ±5% and silver is ±10%. As a multiplier band, gold means ×0.1 and silver ×0.01, which is how sub-10 Ω values are coded: for example brown-black-gold-gold is 10 × 0.1 = 1 Ω ±5%. Position tells you which meaning applies — a lone band at the far end is the tolerance.

### How do I find the color code for a resistance value?

Switch this calculator to **Band Colors** mode, type the resistance, choose the tolerance and it draws the bands for you. By hand: write the value with two significant digits (three for a 5- or 6-band code), convert each digit to its color, then use the multiplier band for the number of zeros — 4.7 kΩ is 4, 7 and ×100, so yellow-violet-red, plus gold for ±5%.

### What is the tolerance range of a resistor?

The tolerance is the guaranteed spread around the nominal value: R × (1 ± t/100). A 4.7 kΩ ±5% resistor is anywhere from 4.465 kΩ to 4.935 kΩ, while ±1% narrows that to 4.653–4.747 kΩ. If a divider or reference depends on the exact ratio, use ±1% or better parts — or measure the ones you have.

## Design the whole board with AI

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