Resistor Color Code Calculator

How to use the resistor color code calculator

1. Choose the Number of bands: 4, 5 or 6. Count every band, including the gold or silver tolerance band.
2. To read a resistor, set each select under Band colors (left to right): the digits, the Multiplier, the Tolerance and, on 6-band parts, the Temperature coefficient. The drawing and the results update at once.
3. To go the other way, type a value in Resistance value (for example 4k7, 4.7k, 220, 1M or 2R2) and press Find colors. The bands are set for you, keeping the tolerance you picked.
4. Read the Resistance, the Tolerance, the Min … max range, the Code (RKM) printed on schematics and the E-series the value belongs to. Copy copies a text summary.
5. Tick Show E-series values to see the nearest standard value in E6, E12, E24, E48, E96 and E192, with the deviation in percent.

How to read the bands

Hold the resistor so that the tolerance band, often gold or silver and usually a little apart from the others, is on the right. Then read from left to right:

• 4 bands: 1st digit, 2nd digit, multiplier, tolerance.
• 5 bands: 3 digits, multiplier, tolerance. Used on precision (1% and better) metal film resistors.
• 6 bands: the same as 5 bands, plus a temperature coefficient band.

The digits follow the IEC 60062 order: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. The multiplier band is a power of ten with the same colors (red = × 100, orange = × 1,000), plus gold × 0.1, silver × 0.01 and pink × 0.001 for low values.

Tolerance colors, per IEC 60062:2016: brown ±1%, red ±2%, orange ±0.05%, yellow ±0.02%, green ±0.5%, blue ±0.25%, violet ±0.1%, grey ±0.01%, gold ±5%, silver ±10%, and no band at all ±20%. Older charts sometimes list grey as ±0.05%. The temperature coefficient band gives the drift in ppm/K: black 250, brown 100, red 50, orange 15, yellow 25, green 20, blue 10, violet 5, grey 1.

Example: yellow, violet, red, gold = 4, 7 × 100 = 4,700 Ω = 4.7 kΩ ±5%, so anything from 4,465 Ω to 4,935 Ω is within specification. On a 6-band resistor with a red tempco band (50 ppm/K), 4.7 kΩ changes by about 0.235 Ω per kelvin.

E-series standard values

Resistors are not sold in every value. The IEC 60063 E-series spread values evenly on a logarithmic scale: E6 has 6 values per decade (tolerance around 20%), E12 has 12 (10%), E24 has 24 (5%), and E48, E96 and E192 serve 2%, 1% and 0.5% parts. This tool tells you whether your value is standard and shows the closest value in each series, which helps when a calculation gives, say, 4.9 kΩ: the nearest E24 value is 5.1 kΩ and the nearest E96 value is 4.99 kΩ.