Resistor colour code calculator for 4, 5 and 6-band resistors: colours to ohms and tolerance, or a value to its bands, snapped to E12, E24 or E96.
Bands yellow, violet, red, gold mark 4.7 kΩ ±5%: any part between 4.465 kΩ and 4.935 kΩ is in spec. The value is in the E6 series.
Bands: yellow, violet → 47; red → ×10^2.
The resistor colour code in IEC 60062 marks a value with coloured bands: two or three significant digits, a multiplier band that gives the power of ten, a tolerance band, and on 6-band parts a temperature-coefficient band. It works both ways here: pick the colours to get the resistance and its tolerance range, or type a resistance to get the bands.
The default, yellow violet red gold, reads 47 × 10² Ω = 4.7 kΩ ±5%, so a part measuring anywhere from 4,465 Ω to 4,935 Ω is in specification. Going from a value to colours, the value can first be snapped to the nearest IEC 60063 preferred value: 5 kΩ is not in E12, so it becomes 4.7 kΩ, yellow violet red.
Gold and silver never start a reading because they carry no digit. When bands are faded or look alike, confirm the value with a multimeter.
Checked against: IEC 60062 table: 4,7 × 10² Ω, gold = ±5%; 4700 × 0.95 / 1.05
Checked against: IEC 60062 table: 100 × 10¹ Ω ±1%
Checked against: IEC 60063 E12 neighbours 4.7k and 5.6k: 5000/4700 = 1.064 < 5600/5000 = 1.12
Checked against: IEC 60062 table: 330 × 10 Ω, brown ±1%, red TCR 50 ppm/K
The first two bands are digits, the third is the multiplier and the fourth the tolerance. The digits run black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. Yellow, violet, red, gold therefore reads 47 × 10² = 4,700 Ω, with gold meaning ±5%.
Start from the end away from the gold or silver band. Gold and silver have no digit value in IEC 60062; they only appear as a multiplier (×0.1 and ×0.01) or a tolerance (±5% and ±10%). The first band usually sits closer to its lead, and the tolerance band is often spaced apart from the others.
A 4-band resistor carries two significant digits, enough for the E6 to E24 values used for ±5% to ±20% parts. A 5-band resistor carries three digits for the E48 to E192 values of ±2% and tighter parts: brown, black, black, red, brown is 100 × 10² Ω = 10 kΩ ±1%. A 6-band resistor adds a temperature-coefficient band.
It gives the resistance drift per kelvin in parts per million: brown 100 ppm/K, red 50, yellow 25, green 20, orange 15, blue 10, violet 5 and grey 1. A 3.3 kΩ resistor with a red band changes by 3,300 × 50 × 10⁻⁶ = 0.165 Ω per degree, about 4.1 Ω over a 25 °C rise.
A missing tolerance band means ±20%. Brown, black, orange with no fourth band is 10 kΩ, and any value from 8 kΩ to 12 kΩ is within specification. Such parts come from the E6 series (1.0, 1.5, 2.2, 3.3, 4.7, 6.8), whose steps of about 47% suit the wide tolerance.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 9 worked examples whose answers come from independent sources; for example, “Yellow violet red gold” is checked against IEC 60062 table: 4,7 × 10² Ω, gold = ±5%; 4700 × 0.95 / 1.05.
IEC 60062:2016 — Marking codes for resistors and capacitors (colour code, tolerance and TCR bands); IEC 60063:2015 — Preferred number series for resistors and capacitors (E series); Wikipedia — Electronic color code (summary of the IEC 60062 table).
9 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
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