This calculator used to reading resistor color code information with 4 or 5 bands. Click on the colors printed to your resistor and the calculated value and tolerance will be displayed.
What is a resistor color code calculator for?
All resistors are color-coded. This allows anyone working with electronics to determine the properties of a resistor just by looking at the colored bands that the resistor has. If one has not memorized the colored codes well enough to be able to tell the properties of the resistor at a glance, an online tool can help them. By inputting the colors of the first, second, third, and fourth bands, one ends up with the resistance, tolerance, minimum, and maximum.
What are resistor color codes used for?
Resistors can have either four bands, five bands, or six bands, depending on how precisely the resistance is being measured. If there are four bands, the four bands have the following meanings:
This is the first significant digit of the resistors total resistance. The numbers are color-coded in the following way:
0 – Black
1 – Brown
2 – Red
3 – Orange
4 – Yellow
5 – Green
6 – Blue
7 – Violet
8 – Grey
9 – White
This is the second significant digit. In the four band resistor, there are only two significant figures worth of accuracy.
This is the multiplier. Since the difference between one resistor and another is immense (from one-hundredth of an Ohm to 10 billion Ohms), a multiplier is used. The values of each multiplier are as follows:
For example, a four-band resistor might have a color code of white (9) and green (5) for its first two bands. The third band in a four-band resistor is a multiplier, with a value of x1000 if the third band is orange. This gives a total value of 9.5*1000 or 9500 ohms worth of resistance. The last band on any resistor determines the tolerance of the resistor. For tolerance, the color codes are as follows:
+/- 1% Brown
+/- 2% Red
+/- 3% Orange
+/- 4% Yellow
+/- 0.5% Green
+/- 0.25% Blue
+/- 0.10% Violet
+/- 0.05% Grey
+/- 5% Gold
+/- 10% Silver
Some resistors have more than four bands. Five or six-band resistors exist. These give more accuracy about how high the resistance is on their color codes. With a six-band resistor, the bands represent the following:
1) First significant digit
2) Second significant digit
3) Third significant digit
4) Fourth significant digit
The last band is always the tolerance, and the second last band is always the multiplier. If the first four bands on a six-band resistor were brown, green, blue, and white, this would give a value of 1.569. The fifth band must be the multiplier because it is the second last. It is yellow, so the multiplier is x10,000. This gives an overall resistance of 15690 Ohms. The final band is silver, so the tolerance is +/- 10 percent. This gives a maximum resistance of 17,259.
a) 5 band resistor with a 4th band of gold or silver
If a resistor has five bands, then the fourth or second last band is the multiplier. Gold and silver multipliers represent a very low level of resistance. With a silver band, the multiplier is 0.1, and with a gold band, it is 0.01. Most currents can easily pass through these resistors. However, there are still some cases in electronics when one needs a resistor that is capable of blocking only a very weak current.
b) Single Black Band or Zero-Ohm resistor
If a resistor has a single black band on it, it offers no or almost no resistance. When building circuit boards, it is sometimes useful to link two points together with a resistor. A zero-ohm resistor can be used in these circumstances. While the resistance of a zero Ohm resistor is not literally zero, it is very low, only about 0.003 Ohms.
If one is working with electronics, they should make as much use of online calculating tools as possible. While one should understand the calculations behind RMS Voltage, Stepper motors, and resistance in parallel, they should not frequently perform these calculations themselves. It is faster and less prone to error to use online tools.
Newbie? Click here to learn how to read resistor values.