BYTETOOLS

Resistor Color Code Calculator

Decode 3, 4, 5 and 6-band resistor color codes to resistance and tolerance, or convert a resistance value back into band colors. Free and instant.

270 kΩ
Resistance
±5%
Tolerance
256.5 kΩ – 283.5 kΩ
Range
—
Tempco

Decoded value

270 kΩ ±5% — this significand is on the E12 and E24 preferred-value series. Decoded with the IEC 60062 color tables.

What is the Resistor Color Code Calculator?

The ByteTools Resistor Color Code Calculator works in both directions. In decode mode, pick the band colors on a 3, 4, 5 or 6-band resistor and read off the resistance, tolerance and (for 6-band parts) the temperature coefficient.

  • Decodes 3, 4, 5 and 6-band resistors
  • Encoder: resistance value → band colors
  • Standard IEC 60062 digit, multiplier, tolerance and tempco tables
  • Live color-band preview drawn in the page
  • Flags E12/E24 preferred values and the min–max range from tolerance
  • 100% private — runs entirely in your browser

How to use the Resistor Color Code Calculator

  1. 1

    Choose the number of bands on your resistor (3, 4, 5 or 6).

  2. 2

    Select each band's color from the dropdowns — the preview updates live.

  3. 3

    Read the resistance, tolerance, min–max range and tempco.

  4. 4

    Or switch to encode mode and type a resistance to get the band colors.

  5. 5

    Copy the result with one click.

About the Resistor Color Code Calculator

The ByteTools Resistor Color Code Calculator works in both directions. In decode mode, pick the band colors on a 3, 4, 5 or 6-band resistor and read off the resistance, tolerance and (for 6-band parts) the temperature coefficient. In encode mode, type a resistance and the tool shows the band colors to look for.

The band values follow the standard IEC 60062 tables used on through-hole resistors worldwide: digit colors black through white, multipliers from ×0.01 (silver) to ×1 G (white), and tolerance colors from ±0.05% grey to ±10% silver. A rendered color-band preview mirrors your selection so you can compare it to the physical part.

The decoder also reports whether the value sits on the E12 or E24 preferred-value series, which helps you spot a misread band. Everything runs 100% locally in your browser — nothing is uploaded, and it works offline at the bench.

Frequently asked questions

How do I read a 4-band resistor color code?

The first two bands are digits, the third is the multiplier and the fourth is the tolerance. For example red-violet-yellow-gold reads as 2, 7, ×10,000 = 270,000 Ω, or 270 kΩ, with ±5% tolerance from the gold band.

What is the difference between 4-band and 5-band resistors?

A 5-band resistor uses three digit bands instead of two, giving an extra significant figure — typical of precision ±1% parts. For example brown-black-black-red-brown is 1, 0, 0, ×100 = 10,000 Ω (10 kΩ) at ±1%.

Which end of the resistor do I read from?

Start from the band closest to a lead end; the tolerance band is usually separated by a wider gap and is often gold or silver. If a gold or silver band exists, it is never the first band, because those colors are only multipliers or tolerances.

What does the sixth band mean?

On 6-band resistors the last band is the temperature coefficient in ppm/K — how much the resistance drifts per degree. Brown is 100 ppm/K, red 50, yellow 25, orange 15, blue 10 and violet 5, per IEC 60062.

What are E12 and E24 values?

They are the standard preferred-value series manufacturers actually produce. E12 has 12 values per decade (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) and E24 has 24. If your decoded value is not on these series, double-check the band colors.

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