6XC

Resistor Color Code Calculator

Pick the color bands on a 4, 5 or 6-band resistor to read its value, or enter a resistance to find the matching bands — with a live visual.

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Resistance—
Tolerance—
Temp. Coefficient—

How the Color Code Works

A resistor's value is printed as colored bands rather than numbers, under the international IEC 60062 standard. Each color stands for a digit 0-9 (black=0, brown=1, red=2, orange=3, yellow=4, green=5, blue=6, violet=7, grey=8, white=9), and the same colors double as multiplier powers of ten on the multiplier band — with gold (×0.1) and silver (×0.01) added so resistors under 10 Ω can still be coded with ordinary digit bands. A 4-band resistor reads as 2 significant digits + multiplier + tolerance; a 5-band resistor adds a third significant digit for tighter precision; a 6th band appends a temperature coefficient in ppm/°C.

Worked example: yellow-violet-red-gold reads as 4-7-×100-±5%: digits 4 and 7 give 47, the ×100 multiplier gives 4700 Ω (4.7 kΩ), and the gold tolerance band means the true resistance falls within ±5% of that — somewhere between 4465 Ω and 4935 Ω.

Resistors are not manufactured at arbitrary values either. Production follows the E12/E24 "preferred value series" — logarithmically spaced standard values (E12: 10, 12, 15, 18, 22, 27, 33…) chosen so that, within a decade, each nominal value's tolerance band just touches its neighbors. E12 steps by roughly the 12th root of 10 (~21%) to cover a full decade with ±10% parts and minimal overlap; E24 halves that step for ±5% parts. That is why color-to-value reads should usually land on, or very near, one of these numbers — a value far from any E-series figure often signals a misread band.

What to Know

  • The tolerance band sets the real-world range, not just a cosmetic detail: gold = ±5%, silver = ±10%, brown = ±1%, red = ±2%. Tighter tolerance means the manufacturer sorted that batch more precisely, and it usually costs more.
  • Reading direction matters. The tolerance band is normally spaced slightly apart from the digit bands — start reading from the opposite end, and check that the multiplier gives a plausible value before trusting the result.
  • 5 and 6-band resistors trade simplicity for precision — the extra significant digit narrows the possible value range before tolerance is even applied, useful for precision timing and reference circuits.
  • Gold and silver as multipliers exist for a reason — they extend the same two/three-digit coding scheme down below 10 Ω without inventing a separate system.

Frequently Asked Questions

What's the difference between 4, 5 and 6-band resistors?

4-band: 2 significant digits + multiplier + tolerance (most common, general-purpose resistors). 5-band: 3 significant digits + multiplier + tolerance (higher precision). 6-band: adds a temperature coefficient band after the tolerance.

Why does gold or silver appear as a multiplier?

For resistors under 10Ω, the multiplier band can be gold (×0.1) or silver (×0.01) instead of a power-of-ten digit color — this lets low-value resistors be coded with the same digit bands.

The value-to-color mode gave me an unusual result — why?

Not every resistance value maps to a standard color combination that a real manufactured resistor would use (see the E12/E24 standard value series) — this tool shows the mathematically correct bands for the number you typed, which is a useful reference even if that exact value isn't a common stocked part.

Why are resistor values like 4.7 kΩ or 22 kΩ so common instead of round numbers?

They come from the E12/E24 preferred value series, spaced logarithmically (roughly every ~21% for E12, ~10% for E24) so that each value's tolerance band just touches the next one — covering every possible resistance with the fewest standard parts and no gaps. A "round" value like 5000 Ω simply isn't on that list.

What's the practical difference between ±1% and ±5% tolerance?

A ±1% (brown band) resistor's true value is guaranteed far closer to nominal than a ±5% (gold band) part — important in precision voltage dividers, filters and timing circuits where a 5% error would shift the result noticeably. General-purpose circuits (pull-ups, LED current limiting) rarely need better than ±5%, which is also cheaper to manufacture.

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