Does this calculator handle 5-band or 6-band resistor color codes?

This tool focuses on 4-band codes where the first two bands are digits, the third is a multiplier, and the fourth is tolerance. Many precision resistors use 5 or 6 bands, adding a third digit, tighter tolerance, or a temperature coefficient; you can still use the two-digit-plus-multiplier idea as a starting point, but those extra bands are not modeled here.

What tolerance should I assume if the calculator does not show it?

For everyday carbon film resistors, gold (±5%) and silver (±10%) are very common tolerance bands. Precision metal film resistors may use brown (±1%), red (±2%), or other colors. When in doubt, check the component datasheet or measure the actual resistance.

Why do some resistors have band colors that don’t match my exact calculated value?

Manufacturers typically produce resistors in standard series (E6, E12, E24, etc.), which means only certain values are available. If your design calls for an unusual resistance, you may need to choose the closest standard value, which may produce slightly different color bands than your ideal calculation.

science calculator

Resistor Color Code Calculator

Convert resistor values into 4-band color codes.

Results

Band 1: yellow
Band 2: violet
Multiplier: red

How to use this calculator

Enter the resistor’s value in ohms as a whole number (for example, 220, 4700, or 100000).
If you are thinking in kilo-ohms or mega-ohms, convert to ohms first (4.7 kΩ → 4700 Ω).
The calculator converts this value to two significant digits and a power-of-ten multiplier.
We map the first digit, second digit, and multiplier onto the standard color chart to identify the first three bands.
Use the output bands to select a resistor from your parts bin or to verify that the bands printed on a resistor match the value you expect.
For most general-purpose carbon film resistors, assume a gold (±5%) or silver (±10%) tolerance band unless you know otherwise.

Inputs explained

Resistance (Ω): The numeric resistance value you want to encode or verify, expressed in ohms. You can convert from kΩ or MΩ by multiplying by 1,000 or 1,000,000, respectively, before entering the value.

How it works

We start from the resistance you enter in ohms and normalize it into scientific notation with two significant digits and a power of ten (for example, 4.7 kΩ becomes 47 × 10² Ω).

The first band is assigned from the first significant digit (0–9), the second band from the second significant digit (0–9), and the third "multiplier" band from the power of ten (10ⁿ).

We map each digit and multiplier to its standard resistor color: black=0, brown=1, red=2, orange=3, yellow=4, green=5, blue=6, violet=7, gray=8, white=9.

The result is a classic 4-band resistor color code: band 1 (first digit), band 2 (second digit), band 3 (multiplier), and an implied tolerance band (often gold or silver on common parts).

Internally, we round to a reasonable precision so common E12/E24 series values produce familiar color codes (like 220 Ω → red-red-brown).

Formula

Normalize resistance R to scientific notation: R ≈ (D1D2) × 10^n where D1 and D2 are the first two significant digits and n is an integer exponent. Map D1 and D2 to digit colors (black=0, brown=1, red=2, orange=3, yellow=4, green=5, blue=6, violet=7, gray=8, white=9) and n to multiplier colors (black=×1, brown=×10, red=×100, orange=×1k, yellow=×10k, green=×100k, blue=×1M, violet=×10M, etc.).

When to use it

Picking the right resistor from a mixed parts bin when the printed bands are hard to read and you want a quick sanity check against a target value.
Double-checking that the resistor you are about to solder into a PCB actually matches the value in your schematic or BOM.
Teaching students and newcomers how the 4-band resistor color code works by tying numeric values directly to color patterns.
Designing circuits where you know the desired resistance in ohms and you want to know what band colors to look for on physical components.

Tips & cautions

If your calculated value does not map cleanly to a standard series (E6, E12, E24), round to the nearest common value to avoid chasing unusual parts.
Tolerance is not included in the calculation; most everyday resistors use gold (±5%) or silver (±10%) tolerance bands. Precision metal film parts may use brown (±1%), red (±2%), or other colors.
Lighting conditions can make similar colors (red/brown, orange/red, blue/violet) hard to distinguish—use a bright, neutral light or a magnifier when in doubt.
For critical circuits, verify the actual resistance with a multimeter rather than relying solely on color bands, especially on older or heat-stressed components.
Remember that the physical orientation matters: start reading bands from the side with the tolerance band farther from the other bands.
Focuses on the classic 4-band code (two digits, multiplier, tolerance). It does not explicitly handle 5-band or 6-band precision resistor codes.
Does not automatically choose a tolerance band; you must infer or read the tolerance from the component itself or from the datasheet.
Assumes you know the target resistance rather than decoding from ambiguous color bands, which may require visual inspection and judgment.
Does not account for specialty resistors such as fusible resistors, thermistors, or SMD parts that use printed codes instead of color bands.

Worked examples

4.7 kΩ general-purpose resistor

Convert 4.7 kΩ to ohms: 4.7 kΩ = 4700 Ω.
Write 4700 Ω as 47 × 10² Ω, so the significant digits are 4 and 7 with a multiplier of 10².
Map 4 → yellow, 7 → violet, and 10² → red.
Result: Yellow–Violet–Red as the first three bands, typically followed by a tolerance band such as gold (±5%).

220 Ω series resistor for an LED

220 Ω can be written directly as 22 × 10¹ Ω.
The first two significant digits are 2 and 2, and the multiplier is 10¹.
Map 2 → red, 2 → red again, and 10¹ → brown.
Result: Red–Red–Brown as the first three bands, with a typical tolerance band like gold (±5%).

Deep dive

Convert resistor values to 4-band color codes in seconds so you can grab the right component for your electronics builds or repairs.

Enter a resistance in ohms to see the first two digit bands and multiplier band that match the standard resistor color chart.

Ideal for students, makers, and technicians who want a fast way to go from numeric resistor values to color band patterns without memorizing tables.

FAQs

Does this calculator handle 5-band or 6-band resistor color codes?: This tool focuses on 4-band codes where the first two bands are digits, the third is a multiplier, and the fourth is tolerance. Many precision resistors use 5 or 6 bands, adding a third digit, tighter tolerance, or a temperature coefficient; you can still use the two-digit-plus-multiplier idea as a starting point, but those extra bands are not modeled here.
What tolerance should I assume if the calculator does not show it?: For everyday carbon film resistors, gold (±5%) and silver (±10%) are very common tolerance bands. Precision metal film resistors may use brown (±1%), red (±2%), or other colors. When in doubt, check the component datasheet or measure the actual resistance.
Why do some resistors have band colors that don’t match my exact calculated value?: Manufacturers typically produce resistors in standard series (E6, E12, E24, etc.), which means only certain values are available. If your design calls for an unusual resistance, you may need to choose the closest standard value, which may produce slightly different color bands than your ideal calculation.

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Resistor color codes are standardized, but printing and aging can make colors harder to distinguish in practice. This calculator provides educational guidance only and should be used alongside a multimeter and manufacturer documentation for critical designs.