How do I know which end to start reading from?

The tolerance band (gold, silver, or a wider gap) is always on the right end. Start reading from the opposite end. On 5-band resistors, the bands are grouped more closely on one side.

Why do some resistors have 5 or 6 bands?

5-band resistors provide three significant digits for higher precision. 6-band resistors add a temperature coefficient band showing how resistance changes with temperature, important for precision circuits.

What are E-series preferred values?

The E12 series has 12 values per decade (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82). E24 has 24 values for 5% tolerance. E96 has 96 values for 1% tolerance. Values are spaced logarithmically.

Are color-coded resistors still used?

Through-hole resistors with color bands are still widely used in hobby electronics, education, prototyping, and repair work. However, most modern commercial products use surface-mount resistors with printed numerical codes.

Resistor Color Code Calculator

Decode 4-band resistor values

Resistor Color Code

Enter the color band values (0-9)

Band 1 (0-9)

Band 2 (0-9)

Multiplier (power of 10)

Formula

R = (Band1 x 10 + Band2) x 10^Multiplier

What Is the Resistor Color Code?

The resistor color code is a standardized system of colored bands printed on resistors to indicate their resistance value and tolerance. Established by IEC 60062, the system uses bands of different colors, each representing a digit, multiplier, or tolerance value. This lets manufacturers mark tiny components without needing to print tiny numbers.

Most common resistors have 4 or 5 color bands. In a 4-band resistor, the first two bands are digits, the third is the multiplier, and the fourth is tolerance. A 5-band resistor adds a third digit for higher precision. Memorizing the color sequence — Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, White (0–9) — is a rite of passage for electronics students.

How to Use This Calculator

Select the number of color bands on your resistor (4-band or 5-band).
Choose the color for each band from the dropdown menus, working left to right.
Click Calculate to see the resistance value in ohms, the multiplier, and the tolerance percentage.
Use the Reset button to decode a different resistor.

Formula & Explanation

4-band: R = (10×d1 + d2) × multiplier ± tolerance
5-band: R = (100×d1 + 10×d2 + d3) × multiplier ± tolerance

d1, d2, d3 = digit values of the first bands. Multiplier = 10^n as shown by the multiplier band. Tolerance is expressed as a percentage (e.g., Gold = ±5%, Silver = ±10%).

Worked Examples

Example 1 — 4-Band: Brown Black Red Gold

Brown = 1, Black = 0, Red = ×100, Gold = ±5%. R = (10×1 + 0) × 100 = 1,000 Ω = 1 kΩ ±5%.

Example 2 — 4-Band: Yellow Violet Orange Silver

Yellow = 4, Violet = 7, Orange = ×1,000, Silver = ±10%. R = 47 × 1,000 = 47,000 Ω = 47 kΩ ±10%.

Example 3 — 5-Band: Red Red Black Brown Brown

Red = 2, Red = 2, Black = 0, Brown = ×10, Brown = ±1%. R = 220 × 10 = 2,200 Ω = 2.2 kΩ ±1%.

Frequently Asked Questions

How do I know which end of the resistor to read from?▾

Read from the end with the band closest to the edge. The tolerance band (gold or silver) is typically on the right. If unsure, try reading both ways and see which gives a standard E-series value.

What does the tolerance band mean?▾

Tolerance indicates how much the actual resistance can deviate from the stated value. Gold = ±5%, Silver = ±10%, Brown = ±1%, Red = ±2%. A 1 kΩ ±5% resistor can be anywhere from 950 Ω to 1,050 Ω.

What is the E-series of resistors?▾

The E-series (E12, E24, E48, E96, E192) defines the preferred resistance values available commercially. E12 has 12 values per decade, E96 has 96. Higher series numbers offer closer tolerance options.

Why are some resistors not color-coded?▾

Surface-mount resistors (SMD) are too small for color bands and instead use a 3- or 4-digit numerical code printed on top. For example, '103' means 10 × 10³ = 10,000 Ω = 10 kΩ.

What is the mnemonic for resistor color codes?▾

A common mnemonic is: 'Better Be Right Or Your Great Big Values Go Wrong' (Black Brown Red Orange Yellow Green Blue Violet Gray White = 0–9). Many variations exist.