Resistor Calculator

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Resistor Color Code Calculator

Select the number of bands and the color of each band to calculate the resistor value, tolerance, and temperature coefficient.

Number of Bands

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Value to Color Code

Enter a resistance value to find the corresponding color code bands. Select the number of bands you want.

Resistance Value

Bands

Tolerance

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Parallel Resistor Calculator

Calculate the total resistance of resistors connected in parallel. Formula: 1/R_total = 1/R₁ + 1/R₂ + ... + 1/R_n

Resistor Values

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Series Resistor Calculator

Calculate total resistance of resistors in series. Formula: R_total = R₁ + R₂ + ... + R_n

Resistor Values

Resistance of a Conductor

Calculate the resistance of a cylindrical conductor from its length, diameter, and material conductivity. Formula: R = L / (A × C)

Length

Diameter

Material

Conductivity (S/m)

Auto-filled from material selection

SMD

SMD Resistor Code Calculator

Decode 3-digit, 4-digit, and EIA-96 SMD (Surface Mount Device) resistor codes. Enter the code printed on the SMD component.

SMD Code

3-digit (472), 4-digit (4702), or EIA-96 (01A)

Code Format

Resistor Guide & Color Code Table

How to Read a Resistor Color Code

4-band: Band 1 & 2 = significant figures, Band 3 = multiplier, Band 4 = tolerance
5-band: Band 1, 2 & 3 = significant figures, Band 4 = multiplier, Band 5 = tolerance
6-band: Same as 5-band + Band 6 = temperature coefficient

Read from left to right. The tolerance band is usually on the right and separated by a gap.

Color	Swatch	Band 1&2 (sig)	Band 3 (5/6-band)	Multiplier	Tolerance	Temp Coeff

Ohm's Law Quick Reference

E-Series Preferred Values (E12)

E12 (10% tolerance): 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82 (and multiples)
E24 (5% tolerance): 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91
Common values: 100Ω, 220Ω, 470Ω, 1kΩ, 2.2kΩ, 4.7kΩ, 10kΩ, 22kΩ, 47kΩ, 100kΩ, 1MΩ