Resistor Color Code Calculator

The Resistor Color Code Calculator reads the coloured bands on any standard 4-band through-hole resistor and converts them into a resistance value in ohms, kilohms, or megohms. Select each band colour from the dropdown — first digit, second digit, multiplier, and tolerance — and see the decoded value with its tolerance range. Includes the full colour code chart and BB ROY mnemonic for quick reference.

Select band colours to decode resistor value, or enter a value to find the colour code.

Band 1 (1st digit) Band 2 (2nd digit) Band 3 (Multiplier) Band 4 (Tolerance)

RESISTANCE

4.7kΩ

4-Band Colour Code Chart

Colour	Digit	Multiplier	Tolerance
Black	0	×1	—
Brown	1	×10	±1%
Red	2	×100	±2%
Orange	3	×1K	—
Yellow	4	×10K	—
Green	5	×100K	±0.5%
Blue	6	×1M	±0.25%
Gold	—	×0.1	±5%
Silver	—	×0.01	±10%

Colour

Digit

Multiplier

Tolerance

Black

×1

—

Brown

×10

±1%

Red

×100

±2%

Orange

×1K

—

Yellow

×10K

—

Green

×100K

±0.5%

Blue

×1M

±0.25%

Gold

—

×0.1

±5%

Silver

—

×0.01

±10%

Reading Order

Hold resistor with grouped bands left, tolerance (gold/silver) right

Band 1 = first digit, Band 2 = second digit

Band 3 = multiplier, Band 4 = tolerance

Mnemonic: BB ROY of Great Britain has a Very Good Wife
Black Brown Red Orange Yellow Green Blue Violet Grey White = 0 1 2 3 4 5 6 7 8 9

Frequently Asked Questions

Which end of a resistor should I read first?

Read from the end opposite the tolerance band. The gold or silver tolerance band is usually spaced slightly farther from the other bands and should be on the right, while the first color band starts on the left.

What do the gold and silver bands mean?

Gold and silver can represent either a multiplier or a tolerance, depending on their position. As tolerance bands, gold means ±5% and silver means ±10%. As multiplier bands, gold represents ×0.1 and silver represents ×0.01.

How do 5-band resistors differ from 4-band resistors?

A 5-band resistor uses three significant digits instead of two, followed by the multiplier and tolerance bands. This provides greater precision for resistor values.

What if a resistor has no tolerance band?

If there is no separate tolerance band, the resistor typically has a tolerance of ±20%. These resistors are less common in modern electronic circuits.

Can this calculator read SMD resistor codes?

No. Surface-mount (SMD) resistors use printed numeric or alphanumeric codes instead of colored bands. This calculator is designed for standard color-coded resistors only.

Is the resistor color code calculator free?

Yes, this resistor color code calculator is completely free to use, requires no sign-up, and instantly converts resistor color bands into resistance values and tolerances.

Resistor Color Code Calculator

4-Band Colour Code Chart

Reading Order

Frequently Asked Questions

Related Calculators

Self-Employment Tax Calculator

Second Pregnancy Due Date Calculator

Savings Withdrawal Calculator

Resting Heart Rate Zone Calculator

Rectangle Area Calculator

Recovery Heart Rate Calculator

Rabbit Age Calculator

RV Loan Calculator

Qibla Direction Calculator

All Categories