What does each band mean?

On a standard 4-band resistor, the first two colored bands are digits (0–9 per the color table), the third band is the multiplier, and the fourth is tolerance. For example, Brown-Black-Red-Gold reads as 1-0-×100-±5%, giving 1,000 Ω (1 kΩ) ±5%.

How do I find the tolerance of a resistor?

The tolerance band is always the last band and is usually separated from the others by a small gap. It is most commonly Gold (±5%) or Silver (±10%) on consumer resistors. Precision resistors use Brown (±1%) or Red (±2%).

Why are resistors color coded instead of printed with numbers?

Resistors are small cylindrical components with rarely enough flat surface to print legible text. Color bands are readable from any angle and survive the high temperatures of wave soldering. The system was standardized by IEC 60062 since the 1920s.

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How to Read Resistor Color Code — Free Calculator (2026)

By Rui Barreira · Last updated: 18 June 2026

Decoding the colored bands on a resistor used to mean memorizing a table. The free resistor color code calculator works in both directions: pick the bands to read a resistance value, or enter a target resistance to find the correct band sequence.

How to Use the Tool

Color → resistance: select each band color from the dropdowns in order from left to right. The tool displays the resistance, tolerance, and multiplier immediately.
Resistance → color: type a resistance value (e.g. 4700 for 4.7 kΩ) and choose the number of bands. The tool returns the matching color sequence you should look for on the component.
Verify the tolerance band (last band) to understand the acceptable range — a 10 Ω ±5% resistor can measure anywhere from 9.5 Ω to 10.5 Ω.

How It Works

The 4-band color code is the most common system for through-hole resistors. The first two bands represent the significant digits of the resistance value. The third band is the multiplier — the power of 10 you multiply the digits by. The fourth band indicates tolerance.

Digit mapping for the first three bands:

Black = 0, Brown = 1, Red = 2, Orange = 3, Yellow = 4
Green = 5, Blue = 6, Violet = 7, Gray = 8, White = 9

Multiplier band: Gold = ×0.1, Silver = ×0.01, Black = ×1, Brown = ×10, Red = ×100, Orange = ×1,000, Yellow = ×10,000, and so on up through White = ×1,000,000,000.

Tolerance band: Gold = ±5%, Silver = ±10%, Brown = ±1%, Red = ±2%, Green = ±0.5%, Blue = ±0.25%, Violet = ±0.1%, Gray = ±0.05%.

5-band and 6-band resistors follow the same pattern with an extra significant digit band; 6-band adds a temperature coefficient band at the end.

Use Cases

Electronics repair — identify an unmarked or faded resistor on a PCB without needing a multimeter.
Prototyping — confirm you picked the right resistor from your parts bin before it goes into the breadboard.
PCB design verification — cross-check a BOM value against the physical component during assembly.
Teaching and learning — students can practice reading codes interactively and get instant feedback.
Sourcing — look up the correct color sequence when ordering specific resistor values.

Frequently Asked Questions

What does each band mean?: On a standard 4-band resistor, the first two colored bands are digits (0–9 per the color table), the third band is the multiplier, and the fourth is tolerance. For example, Brown-Black-Red-Gold reads as 1-0-×100-±5%, giving 1,000 Ω (1 kΩ) ±5%.
How do I find the tolerance of a resistor?: The tolerance band is always the last band and is usually separated from the others by a small gap. It is most commonly Gold (±5%) or Silver (±10%) on consumer resistors. Precision resistors use Brown (±1%) or Red (±2%) in this position on a 5-band or 6-band body.
Why are resistors color coded instead of printed with numbers?: Resistors are small cylindrical components — there is rarely enough flat surface to print legible text on all orientations. Color bands are readable from any angle and survive the high temperatures of wave soldering and reflow processes that would smear ink. The system was standardized by IEC 60062 and has been in use since the 1920s.

Frequently Asked Questions

What does each band mean?: On a standard 4-band resistor, the first two colored bands are digits (0–9 per the color table), the third band is the multiplier, and the fourth is tolerance. For example, Brown-Black-Red-Gold reads as 1-0-×100-±5%, giving 1,000 Ω (1 kΩ) ±5%.
How do I find the tolerance of a resistor?: The tolerance band is always the last band and is usually separated from the others by a small gap. It is most commonly Gold (±5%) or Silver (±10%) on consumer resistors. Precision resistors use Brown (±1%) or Red (±2%).
Why are resistors color coded instead of printed with numbers?: Resistors are small cylindrical components with rarely enough flat surface to print legible text. Color bands are readable from any angle and survive the high temperatures of wave soldering. The system was standardized by IEC 60062 since the 1920s.