Resistors use colored bands to indicate their resistance value and tolerance. The most common types are 4-band and 5-band resistors.
How do I know if a resistor is 4-band or 5-band?
4-band resistors have 2 significant digits, a multiplier, and a tolerance band. 5-band resistors use 3 significant digits, a multiplier, and a tolerance. 5-band resistors are usually precision components.
Which side do I start reading from?
Look for the band separated by a larger gap. The tolerance band (often Gold, Silver, or Brown) is usually on the far right. Start reading from the other end.
What does the gold or silver band mean?
Gold/Silver usually indicate Tolerance (±5% or ±10%) if at the end. If in the 3rd or 4th position, they act as fractional multipliers (×0.1 or ×0.01).
What does tolerance (±1%, ±5%) actually mean?
It defines the range of actual resistance. For example, a 1kΩ resistor with ±5% tolerance can measure anywhere between 950Ω and 1050Ω.
Can the first band be black?
No. The first significant digit cannot be zero. That is why Black is not an option for Band 1 in standard color codes.
Do you support 6-band resistors (Tempco)?
Not currently. A 6-band resistor adds a Temperature Coefficient (ppm/°C) band. This tool focuses on standard 4 and 5-band resistors.