numvana

4-Band Resistor Color Code Calculator

Decode a 4-band resistor's color bands into its resistance value and tolerance, using the standard EIA/IEC color code.

Resistance
4.7 kΩ
Tolerance
±5%
Acceptable range
4.465 kΩ – 4.935 kΩ

How it works

This decodes a standard 4-band resistor using the EIA/IEC 60062 color code — the fixed industry-wide reference table printed on every resistor of this type, not a value that changes over time. The first two bands are significant digits 0–9 (black through white); the third band is a power-of-ten multiplier (or ×0.1 / ×0.01 for gold/silver); the fourth band is a fixed tolerance percentage.

Resistance is (first digit × 10 + second digit) × multiplier. For example, yellow-violet-red-gold decodes to digits 4 and 7, multiplier ×100, giving 47 × 100 = 4,700 Ω (4.7 kΩ) at ±5% tolerance — a very common resistor value.

The acceptable range shown is the resistance value adjusted up and down by the tolerance percentage — the actual measured resistance of a real resistor with these bands should fall somewhere in that range, due to normal manufacturing variance.

FAQ

Which end of the resistor is band 1?

Band 1 is the band closest to one end of the resistor, read moving away from that end toward the tolerance band, which is usually spaced slightly apart from the other three and is often gold or silver. If a resistor could be read either direction, the correct reading is the one that puts the tolerance-colored band last.

What about 5-band or 6-band resistors?

Those use a third significant digit (for higher precision) and, for 6-band resistors, an added temperature coefficient band — a different layout from the 4-band code this calculator decodes.

Related calculators