Resistor Color Code Decoder

The tolerance band (Gold, Silver, or no band) is always read last — start from the opposite end. If bands are evenly spaced, look for a slightly wider gap between the last significant-digit band and the multiplier band; the tolerance band is on the far side of that gap. When in doubt, check both orientations: one will produce a value in a standard E-series, the other often won't.

Tolerance is the maximum allowed deviation from the labelled value. A 4.7 kΩ ±5% resistor can measure anywhere from 4.465 kΩ to 4.935 kΩ and still be within spec. For precision circuits, use ±1% (brown band) or better metal-film resistors.

Temperature coefficient (ppm/°C) tells you how much the resistance changes per degree Celsius. A 10 kΩ resistor with 100 ppm/°C will drift by roughly 1 Ω for every 1 °C change. This matters in precision voltage references, oscillators, and sensor signal paths.

E12 has 12 values per decade, spaced for ±10% tolerance. E24 has 24, for ±5%. E96 has 96, for ±1%. The tighter the tolerance, the more standard values are needed to ensure adjacent values don't overlap their tolerance bands. E96 is used for precision metal-film resistors.

The tolerance band (Gold, Silver, or no band) is always the last band — start from the opposite end. If unsure, check both orientations: one usually maps to a standard E-series value, the other won't.

Surface-mount resistors are too small to print readable color bands. Common systems: 3-digit (e.g. 472 = 47 × 10² = 4.7 kΩ), 4-digit for tighter tolerances (e.g. 4702 = 47.0 kΩ), and EIA-96 for 1% resistors (a two-digit code plus a multiplier letter, e.g. 01C = 100 Ω).

Nothing standardised — it is just the manufacturer's coating material. In practice, tan/beige bodies are typically carbon film (±5%), and blue or light-green bodies are often metal film (±1% or ±2%). This is a convention, not a standard; always read the bands rather than relying on body color.

Carbon film resistors (usually tan, ±5%) are lower cost and adequate for general-purpose use. Metal film resistors (usually blue, ±1%) have tighter tolerance, lower temperature coefficient (50–100 ppm/°C vs 200–500 ppm/°C for carbon film), and lower noise — preferred for precision circuits, audio, and sensor signal paths.

No. Resistors are manufactured in standard E-series values (E12, E24, E96, E192). If you need 3.7 kΩ, you won't find it on a distributor shelf — the nearest E24 values are 3.6 kΩ and 3.9 kΩ. Design around standard values, or combine two resistors in series or parallel to hit an unusual target.