Resistance Calculator

Resistance Calculator: You can quickly and easily determine the resistance of your element using this resistor colour code calculator. Simply select the number of bands your resistor has - 4, 5, or 6, and the colours you want, and in a flash, you'll have the resistance, tolerance, range, and temperature coefficient value (if you chose the 6 band resistor colour code). If you want to learn how to read a resistor colour code, scroll down to see formulas and explanations.

Resistor Color-Coding

Due to their small size, resistors with low wattage ratings are colour-coded to indicate their resistive value, tolerance, and temperature coefficient. Because colour bands can be easily and inexpensively printed on a small electronic component, they are used. Capacitors, inductors, and diodes all have colour-coding.

The resistance value, tolerance, and wattage are usually printed on the resistor body surface whenever the resistor body surface is huge enough, as in large wattage resistors. Surface-mounted resistors (SMDs) use an alternative coding system that uses alphanumeric codes printed on the resistor's surface rather than colour codes.

The international standard IEC 60062:2016 establishes the coding. Both resistors and capacitors have a coding standard.

Reading Colour Codes

The resistance, tolerance, and temperature coefficient of resistance of resistors are usually indicated by three to six bands on their cases (TCR). From left to right, the bands are read. The direction of reading is not always obvious.

The tolerance bandwidth is sometimes 1.5 - 2 times the width of other bands to distinguish the reading direction. There is sometimes a larger gap between the tolerance band and the other bands. If there is a gold or silver band, it must be at the right end, as it is never used for significant digits. To get the exact resistance value, always check the manufacturer's documentation or use a multimeter.

  • The first two bands of a three-band resistor represent the first two significant digits, followed by a band for the multiplier. Because there is no tolerance band, the tolerance will always be 20%.
  • The first two bands of a four-band resistor, which is the most common, also represent the first two significant digits. The multiplier is represented by the third band. Tolerance is represented by the fourth band.
  • The first three bands of a five-band resistor represent the first three significant digits. The multiplier is represented by the fourth band. The fifth band is dedicated to tolerance.
  • The first five bands of a six-band resistor have the same representation as a five-band resistor, with one additional sixth band representing the temperature coefficient of resistance (TCR).

What is the purpose of resistor colour codes?

Instead of printed text, a colour code is used to indicate the value, rating, or tolerance for very small electronic components.

Resistors are available in four, five, or more colour bands, with a four-band colour code being the most common. The first and second bands represent the ohm value's first and second significant digits, respectively, and the decimal multiplier is represented by the third band.

After that, there's a small gap to help you distinguish between the component's left and right sides, followed by the fourth band, which indicates the resistor's tolerance.

Colours for Significant Figures

black: 0

brown: 1

red: 2

orange: 3

yellow: 4

green: 5

blue: 6

violet: 7

grey: 8

white: 9

Colours for multiplier band:

black: 1

brown: 10

red: 100

orange: 1000

yellow: 10000

green: 100000

blue: 1000000

gold: 0.1

silver: 0.01

How to use the Resistance Calculator?

Follow these simple instructions to use the calculator:

  • Step 1: Choose the number of bands on the resistor you're looking for.
  • Step 2: Select the matching colour in the table column indicating the band number for each band.
  • Step 3: The resistance value, as well as the minimum and maximum values, will be calculated and displayed.

FAQs on Resistance Calculator

1. Who invented the colour code for resistors?

The Radio Manufacturers Association created the colour code in the 1920s (RMA).

2. What is the purpose of a resistor colour code?

The bands on resistors are made up of several colour bands that together specify the resistance value, tolerance, and, in some cases, reliability rate. High-precision resistors have five bands. The first three bands represent the significant digits, the fourth band represents the multiplying factor, and the fifth band represents the tolerance.

3. What is the significance of colour coding resistors?

Resistors are typically small, printing resistor values on them are difficult. As a result, colour bands representing electrical resistance are printed on them.

4. What is the best way to remember the resistor colour code?

A mnemonic device can be used to remember the resistor colour codes. The capital letters represent the first letters of the colours, and their positions represent the digit values. "BB ROY of Great Britain had a Very Good Wife," the capital letters represent the first letters of the colours, and their positions represent the digit values.

5. For a 1000 ohm resistor, what is the colour code?

A four-band colour code for a 1000 ohm resistor ranges from brown to black to red to gold. The 1000 resistor has a 100 (Red) multiplier factor and a 5% tolerance level (Gold).