๐จ Resistor Color Code Calculator
Select the color bands on a resistor to calculate its resistance value and tolerance based on the standard EIA resistor color code. Supports both 4-band and 5-band resistors.
How to use
- Choose 4-band or 5-band mode.
- Select each bandโs color to match your physical resistor.
- The resistance and tolerance are calculated automatically.
How the calculation works
Resistor colour codes (IEC 60062) show a resistor's value and tolerance with coloured bands. This tool handles 4-band and 5-band resistors. 4 bands: bands 1โ2 are digits, band 3 is the multiplier (a power of 10), band 4 the tolerance 5 bands: bands 1โ3 are digits, band 4 the multiplier, band 5 the tolerance Colours: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9 Multiplier gold ร 0.1, silver ร 0.01 Tolerance: brown ยฑ1%, red ยฑ2%, green ยฑ0.5%, blue ยฑ0.25%, violet ยฑ0.1%, grey ยฑ0.05%, gold ยฑ5%, silver ยฑ10%, no band ยฑ20% Resistance = the digits read as a number ร 10^(multiplier)
Worked example
Brown, black, red, gold (4 bands) 1, 0 โ 10 ร 10ยฒ = 1,000 ฮฉ = 1 kฮฉ, ยฑ5% Yellow, violet, orange, gold 47 ร 10ยณ = 47 kฮฉ ยฑ5% Brown, black, black, brown, brown (5 bands) 100 ร 10ยน = 1 kฮฉ ยฑ1%
Things to be aware of
- Hold the resistor with the tolerance band (often gold or silver) on the right; the slightly wider gap is usually on that side.
- Mnemonics such as "Bad Beer Rots Our Young Guts But Vodka Goes Well" help remember the colour order.
- Old or heat-discoloured parts are easy to misread; confirm with a multimeter.
FAQ
What color code standard does this use?
It uses the standard EIA resistor color code. The mapping of digit colors (black through white), multiplier colors, and tolerance colors (gold, silver, etc.) is internationally standardized.
Whatโs the difference between 4-band and 5-band?
4-band resistors encode 2 significant digits, while 5-band resistors encode 3 significant digits for higher precision.
What if the colors are hard to distinguish on my resistor?
Lighting conditions and component wear can make colors hard to read. If possible, verify with a multimeter reading.