Resistor Color Code Calculator
Decode 4-band resistor colors to ohms and tolerance instantly
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Need to decode 4-band resistor colors to ohms and tolerance instantly? Resistor Color Code Calculator answers in seconds. Drop your values into Resistor Color Code — the figure refreshes as you type. Resistor Color Code prints the result and its working. Resistor Color Code suits budgeting and planning checks. Nothing typed into Resistor Color Code leaves your device or the tab. Resistor Color Code handles resistor color code the same way as 4 band resistor — one of the Tech & Digital tools on CalcProMaster. Resistor Color Code has no learning curve. The fields are labeled. Resistor Color Code is free, instant and local.
What 4-7-100-5% decodes to
First band 4, second band 7, multiplier ×100, tolerance ±5%: 4.7 kΩ, tolerance ±5%.
Read as digits: 4 and 7 form 47, then the multiplier adds two zeros — 4,700 Ω. The kΩ prefix is just a convenience for the same value.
How a four-band code is read
Band 1 is the first digit, band 2 the second, band 3 the multiplier, band 4 the tolerance. There is no third digit in a four-band code; the third band tells you how many zeros to append.
Worked example
Band 1 = 4
Band 2 = 7
Band 3 = ×100
(47 × 100) = 4,700 Ω = 4.7 kΩ
Band 4 = ±5%
The tolerance band matters as much as the value: ±5% on 4.7 kΩ is ±235 Ω, so anything from 4,465 to 4,935 Ω is in specification. A ±1% part would be within 47 Ω.
The colour table
- Black 0 · Brown 1 · Red 2 · Orange 3 · Yellow 4
- Green 5 · Blue 6 · Violet 7 · Grey 8 · White 9
- Gold ×0.1 and ±5% · Silver ×0.01 and ±10%
Which way round
Start from the end with the tolerance band — gold or silver, or simply the band with more space before it. A resistor with bands evenly spaced and no metallic band is ambiguous, and a multimeter is faster than guessing.
Mistakes worth avoiding
- Reading the multiplier as a third digit. 4-7-2 is 47 × 100, not 472 Ω.
- Confusing brown and red under poor light — 1 and 2 differ by a factor of ten in the multiplier position.
- Expecting a five-band code to read the same way; there the third band is a real third digit.
- Assuming the measured value must be exact. A 4.7 kΩ ±5% part reading 4.6 kΩ is correct.
Frequently Asked Questions
What is 47 × 100 in ohms?
4,700 Ω, which is written 4.7 kΩ. Two digits from the first two bands, then two zeros from the ×100 multiplier.
Which band is the tolerance?
The last one, usually gold (±5%) or silver (±10%), and often set slightly apart from the others. Brown is ±1%, red ±2%, and no fourth band means ±20%.
How do I read a five-band resistor?
Bands 1–3 are digits, band 4 is the multiplier and band 5 is the tolerance. A 4-band code has only two digits, so the same colours mean a different value.
What does ±5% mean in practice?
The true resistance is within 5% of the marked value — for 4.7 kΩ, between 4,465 and 4,935 Ω. That spread is normal and usually irrelevant in a circuit designed around it.
What if the resistor has only three bands?
The tolerance is ±20%, the default when no fourth band is printed. Three-band parts are older and less common.
What colours make 10 kΩ?
Brown, black, orange — 1 and 0 making 10, multiplied by 1,000 — with gold for ±5%. For 1 kΩ it is brown, black, red; for 100 Ω it is brown, black, brown. The first two bands stay the same; only the multiplier moves.
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