Resistance Calculator To Calculate Ohm Value of Resistor

This ohm resistance calculator will readily calculate resistance and tolerance of an electrical circuit based on colour codes. Also computes conductor’s resistance based on conductivity and size values entered. Moreover, you could estimate the combined series or parallel resistance with the tool.

What Is Resistance?

Something that forces the electric current not to flow is known as the resistance.

How To Calculate Resistance?

Following are the standard voltage current resistance formulas to measure resistance:

Colour Codes:

Colour codes correspond to the ratings that define the potential of certain electrical components. But we have considered the codes for resistances only.

Hold the resistance in your hand with tolerance bands to the most right
Start noticing bands one by one from left to right and pick a value from the table (against colour) to estimate the desired ohm value.

For instance, the following pictures will let you understand pattern to calculate ohm value that you are holding:

3 Band Resistor:

4 Band Resistor:

5 Band Resistor:

6 Band Resistor:

Our electrical resistance calculator takes into account the table below to decode the colour code into value:

Color	1st, 2nd, 3rd Band Significant Figures	Multiplier	Tolerance	Temperature Coefficient
Black	0	× 1		250 ppm/K (U)
Brown	1	× 10	±1% (F)	100 ppm/K (S)
Red	2	× 100	±2% (G)	50 ppm/K (R)
Orange	3	× 1K	±0.05% (W)	15 ppm/K (P)
Yellow	4	× 10K	±0.02% (P)	25 ppm/K (Q)
Green	5	× 100K	±0.5% (D)	20 ppm/K (Z)
Blue	6	× 1M	±0.25% (C)	10 ppm/K (Z)
Violet	7	× 10M	±0.1% (B)	5 ppm/K (M)
Grey	8	× 100M	±0.01% (L)	1 ppm/K (K)
White	9	× 1G
Gold		× 0.1	±5% (J)
Silver		× 0.01	±10% (K)
None			±20% (M)

Serial Resistance:

\(R_{total} = R_{1}+R_{2}+R_{3}+R_{4}+R_{5}+...+R_{n}\)

Parallel Resistance:

\(R_{total} = \dfrac{1}{\dfrac{1}{R_{1}}+\dfrac{1}{R_{2}}+\dfrac{1}{R_{3}}+\dfrac{1}{R_{4}}+\dfrac{1}{R_{5}}+...+\dfrac{1}{R_{n}}}\)

Conductor Resistance:

\(R = \dfrac{L}{A*C}\)

Where;

L = Length of Conductor

A = Cross Sectional Area of the Conductor

C = Material’s Conductivity

How Does Our Circuit Resistance Calculator Work?

Calculating resistance with our calculator is quite easy and swift. Let’s learn its usage!

Input:

Please select the resistance method from the top list there on tool
Once you are done with your choice, go by entering the values or selecting colour combinations for your resistances
Hit the calculate button

Output:

Resistance calculations for conductors and circuits

References:

From the source of Wikipedia: Electrical resistance and conductance, Ohm's law, Static and differential resistance, AC circuits, Energy dissipation and Joule heating From the source of Khan Academy: Current, do electrons in alternating current circuits From the source of Coursehero: Resistors, Temperature and Superconductivity, Resistivity

1^st Band Color:
black	brown	red	orange	yellow
green	blue	violet	grey	white
2^nd Band Color:
black	brown	red	orange	yellow
green	blue	violet	grey	white
3^rd Band Color:
black	brown	red	orange	yellow
green	blue	violet	grey	white
Multiplier Color:
black	brown	red	orange	yellow
green	blue	violet	grey	white
gold	silver
Tolerance Color:
brown	red	orange	yellow	green
blue	violet	grey	gold	silver
Temperature Coefficient Color:
black	brown	red	orange	yellow
green	blue	violet	grey