How to read the bands
Hold the resistor with the tolerance band (usually gold or silver, sitting apart from the others) on the right — that fixes the reading direction. The remaining bands read left to right: two or three digit bands, then a multiplier band.
- digits — the 2 (4-band) or 3 (5-band) leading bands, read as a number
- multiplier — power-of-ten band: black=×1 up to white=×1,000,000,000, gold=×0.1, silver=×0.01
- tolerance — last band: brown=±1%, red=±2%, green=±0.5%, blue=±0.25%, violet=±0.1%, gray=±0.05%, gold=±5%, silver=±10%
More detail
The most common misread: which end is first
The tolerance band is the tell — it's almost always gold or silver and sits with more space before it than the digit bands have between each other. Reading a resistor backwards (tolerance band first) is the single most common color-code mistake, and it produces a completely different value, not just a slightly-off one. If your result looks implausible for the circuit you're building, try reversing the band order first.
Why 5-band resistors exist
A 4-band code has only two significant digits, so it can't express a value like 4.99 kΩ precisely — it rounds to the nearest step on the E24 series. A 5-band code adds a third digit for one more significant figure, which is how 1% and tighter tolerance parts (E96 series) get built: a looser digit resolution would make the tighter tolerance band meaningless.
Reading tip. Gold and silver only ever appear as a multiplier or tolerance band, never as a digit band. If a select above shows gold or silver in a digit position, the calculator will correctly show "—" — that combination doesn't exist on a real resistor.
Frequently asked questions
What value is red-red-brown-gold?
Digits 2, 2 → 22. Multiplier brown → ×10 → 220 Ω. Tolerance gold → ±5%, so the part reads anywhere from 209 Ω to 231 Ω.
What value is brown-black-red-gold?
Digits 1, 0 → 10. Multiplier red → ×100 → 1,000 Ω (1 kΩ). Tolerance gold → ±5%, a range of 950–1,050 Ω.
How is a 5-band code different from 4-band?
5-band adds a third digit band before the multiplier: brown-black-black-red-brown reads digits 1, 0, 0 → 100, ×100 → 10 kΩ, tolerance brown → ±1% (9,900–10,100 Ω) — one more digit of precision than a 4-band code can express.
Can gold or silver be a digit band?
No. Gold (×0.1) and silver (×0.01) are only valid as the multiplier or tolerance band. Select either one for a digit band above and the result shows "—", since no real resistor is manufactured that way.