Resistor Color Code Calculator
Read the resistance and tolerance from the color bands painted on a leaded resistor. Choose 4 or 5 bands and the colors, and the drawing and value update. You can also enter a resistance to find its color code.
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Value
- Resistance
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- Tolerance
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- Range
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Find the colors for a resistance
- 4 bands
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- 5 bands
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The color-to-digit mapping follows the international standard IEC 60062. When the lookup has to round to the available digits, the rounded value is shown in parentheses.
See it as a graph
Other inputs stay at their current values while the chosen input varies from 1/4 to 4 times its current value. The red dot is the current value.
Reading 4-band and 5-band codes
On a 4-band resistor, the first two bands are digits, the third is the multiplier (a power of ten) and the fourth is the tolerance. The digit colors are black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8 and white 9. The default brown–black–red–gold reads 10 × 10² = 1000 Ω, or 1 kΩ ±5%, so the actual value lies between 950 Ω and 1.05 kΩ. A 5-band resistor has three digit bands, so brown–black–black–brown–brown is 100 × 10 = 1 kΩ ±1%. The extra digit allows finer values, which is why 5-band codes are common on tighter-tolerance resistors.
Which end to start from
Several clues show the direction. The tolerance band is usually set slightly apart from the others, and the first band sits closer to the end of the body. Gold and silver are not digits, so they never appear as the first band; on a 4-band resistor with gold or silver at one end, that band is the last one. Precision 5-band resistors often have a brown (±1%) tolerance band, so both ends can be brown. In that case, read the code both ways and choose the direction that gives a value in an E-series, or measure the resistance with a multimeter.
Gold and silver multipliers, and tolerance colors
When the multiplier band is a digit color, it means ten to that power (black ×1, brown ×10, red ×100, orange ×1000 and so on), while gold means ×0.1 and silver ×0.01. Yellow–violet–gold–gold, for example, is 47 × 0.1 = 4.7 Ω ±5%, a way to mark values below 10 Ω. The tolerance colors are brown ±1%, red ±2%, green ±0.5%, blue ±0.25%, violet ±0.1%, gold ±5% and silver ±10%. A resistor with only three bands (no tolerance band) is generally ±20%. In reverse, the default 4700 Ω is yellow–violet–red in 4 bands and yellow–violet–black–brown in 5 bands, followed by the tolerance band.
E-series and values like 4.7 kΩ
Commercial resistor values come from preferred-number series called the E-series (IEC 60063). E6, E12 and E24 divide each decade into 6, 12 and 24 steps, with a nearly constant ratio between neighbors (about 1.47 for E6 and 1.21 for E12). E12 is 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8 and 8.2. In a geometric sequence the fifth E6 step is 10^(4/6) ≈ 4.64, which rounds to 4.7. E12 is generally paired with ±10% tolerance and E24 with ±5%, so that the tolerance range of each value roughly meets that of its neighbors.
Practice analog circuit questions
FAQ
How can I tell which end of a resistor to read first?
Generally the band closest to one end of the body is the first band, and the band set slightly apart is the tolerance. Gold and silver are not digits and never come first, so on a 4-band resistor with gold or silver at one end, that band is the last one. If you still can't tell, read it both ways and pick the direction that gives an E-series value, or measure it with a multimeter.
What does a sixth band mean?
On 6-band resistors, the sixth band is generally a temperature coefficient band added after the three digits, multiplier and tolerance of a 5-band code. The temperature coefficient, in ppm/K, shows how much the resistance changes for each 1 K change in temperature and matters in precision circuits. The colors are assigned to coefficients by a table in the standard, so check the datasheet or the standard. This tool handles 4-band and 5-band codes.
Why are there values like 4.7 kΩ instead of 5 kΩ?
Resistor values come from the E-series, which split each decade in nearly equal ratios. In E6 the values rise by about 1.5 times each step, 1.0 → 1.5 → 2.2 → 3.3 → 4.7 → 6.8, and 4.7 is 10^(4/6) ≈ 4.64 rounded. Geometric spacing lets the tolerance ranges of neighboring values line up with few gaps. 5.0 is not in E24 either, although E24 does include 5.1.