About the Resistor Color Code Calculator
This resistor color code calculator turns the colored stripes on a through-hole resistor into its resistance, tolerance range and (for 6-band parts) temperature coefficient. Select the number of bands, pick each color from left to right, and the value appears in ohms, kilohms or megohms along with the minimum and maximum resistance the tolerance allows.
It also works in reverse: choose "find colors", type a resistance such as 330 or 4990 Ω, and it lists the band colors to look for in a parts drawer. That is handy when sorting a kit, checking a bill of materials or teaching the code to students.
Read the resistor with the tolerance band — usually gold, silver or a band set slightly apart — on the right. 4-band resistors have two significant digits, 5- and 6-band precision resistors have three. The colors follow the international standard IEC 60062.
How to use the resistor color code calculator
- 1Turn the resistor so the tolerance band (gold, silver or the spaced-apart band) is on the right.
- 2Choose 4, 5 or 6 bands to match your resistor.
- 3Select each band color from left to right.
- 4Read the resistance and its tolerance range — or pick "find colors" and type a value to get its bands.
Formula and method
The first two bands (three on 5- and 6-band resistors) are significant digits: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. The next band is a power-of-ten multiplier using the same colors, plus gold (×0.1) and silver (×0.01).
The tolerance band gives the allowed deviation: brown ±1%, red ±2%, green ±0.5%, blue ±0.25%, violet ±0.1%, gold ±5%, silver ±10%, and no band ±20%. A sixth band states the temperature coefficient in ppm per kelvin. To encode a value, the calculator rounds it to two or three significant digits and picks the multiplier color for the remaining power of ten.
- R
- Nominal resistance in ohms
- multiplier
- Power of ten from the multiplier band (−2 to 9)
- tolerance
- Allowed deviation from the tolerance band
Worked examples
Yellow–violet–red–gold (4-band)
Yellow = 4 and violet = 7 give 47; red multiplies by 100, so R = 4,700 Ω = 4.7 kΩ. Gold means ±5%, so a good part measures between 4,465 and 4,935 Ω.
Brown–black–black–red–brown (5-band)
The digits 1-0-0 make 100, and red multiplies by 100 to give 10,000 Ω (10 kΩ). The brown tolerance band means ±1%, i.e. 9,900–10,100 Ω.
Red–red–black–brown–brown–brown (6-band)
Digits 2-2-0 = 220, the brown multiplier ×10 gives 2,200 Ω. The second-to-last brown band is ±1% tolerance and the last brown band is a 100 ppm/K temperature coefficient.
Find the colors for 330 Ω
330 = 33 × 10¹, so the digits are orange (3), orange (3) and the multiplier is brown (×10), followed by gold for ±5%.
Find 5-band colors for 4.99 kΩ, 1%
4,990 = 499 × 10¹: yellow (4), white (9), white (9), brown multiplier (×10), then brown for ±1%.
Frequently asked questions
Which end of a resistor do you read from?+
Read from the end opposite the tolerance band. The tolerance band is usually gold or silver, or is separated from the others by a wider gap. The first band is normally closer to the lead.
What is the difference between 4-band and 5-band resistors?+
A 4-band resistor has two significant digits, a multiplier and a tolerance band, and is typically ±5%. A 5-band resistor has three significant digits for precision values such as 4.99 kΩ, usually ±1% or better.
What does the 6th band on a resistor mean?+
The sixth band is the temperature coefficient: how much the resistance changes per degree of temperature, in parts per million per kelvin. Brown is 100 ppm/K, red 50 ppm/K and so on.
Is there a mnemonic for the resistor color code?+
A common one is "Big Brown Rabbits Often Yield Great Big Vocal Groans When Gingerly Snapped" for black, brown, red, orange, yellow, green, blue, violet, grey, white, gold, silver.
What if my value is not a standard resistor value?+
Resistors are made in E-series steps (E12, E24, E96). If your calculated value is not available, pick the nearest standard value or combine two resistors in series or parallel.