Resistor Identifier
Decode leaded resistor colour bands and common SMD resistance markings.
Resistor Identifier
How to use the Resistor Identifier
Choose the leaded band colours or enter an SMD code to identify the nominal resistance, tolerance and code format.
How it works
Leaded resistors encode their nominal resistance with coloured bands. Most four-band parts use two significant digits followed by a multiplier and tolerance; five-band precision parts use three significant digits. Surface-mount resistors commonly use three- or four-digit codes, R-decimal notation or the EIA-96 system.
Example: Brown, black, red and gold represents 10 × 100 Ω, giving 1 kΩ with ±5% tolerance. An SMD marking of 472 represents 47 × 10² Ω, also written as 4.7 kΩ.
What to keep in mind
Markings can be tiny, damaged or manufacturer-specific, and some low-value or specialist parts use other conventions. Circuit connections can affect a meter reading, so isolate power and lift one resistor lead when an accurate confirmation is required.
Frequently asked questions
Which end of a leaded resistor should I read first?
Start at the end where the bands are grouped closest together. The tolerance band is often spaced farther away and is commonly gold, silver, brown or red.
What does R mean in an SMD code?
It replaces the decimal point. For example, 4R7 means 4.7 ohms and R22 means 0.22 ohms.
What is an EIA-96 marking?
It uses a two-digit lookup code for an E96 value followed by a letter multiplier, typically on 1% SMD resistors.
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