Free calculator
Resistor colour code calculator
Small through-hole resistors show their value with coloured bands. Tap the colours you see to read the value, or type a value to see which bands it has.
Resistance
- Lowest it can be
- 950 Ω
- Highest it can be
- 1.05 kΩ
- Standard value?
- Yes, E12
How the code works
Each colour stands for a digit:
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | × 1 | |
| Brown | 1 | × 10 | ±1% |
| Red | 2 | × 100 | ±2% |
| Orange | 3 | × 1,000 | |
| Yellow | 4 | × 10,000 | |
| Green | 5 | × 100,000 | ±0.5% |
| Blue | 6 | × 1,000,000 | ±0.25% |
| Violet | 7 | × 10,000,000 | ±0.1% |
| Grey | 8 | ±0.05% | |
| White | 9 | ||
| Gold | × 0.1 | ±5% | |
| Silver | × 0.01 | ±10% |
On a 4-band resistor, the first two bands are digits, the third is the multiplier and the fourth is the tolerance. A 5-band resistor has three digits before the multiplier.
A worked example
Yellow, violet, red, gold: 4 and 7 make 47, red multiplies by 100, so it's 4,700 Ω = 4.7 kΩ, within ±5%. Anything from 4,465 Ω to 4,935 Ω is in spec.
Free lesson
Now build it yourself
Each lesson comes in three short parts: see the idea, try it on a live board, then build it yourself, with quick checks as you go.
“Resistance: the squeeze” is lesson 4 of 6 in Copper Flats, Electronics World 1. Free with an account. Lessons unlock in order, so you’ll do the 3 before it first.
Or start from the very first lesson, no account neededThe ideas behind it
Questions people ask
How do you read a resistor's colour code?
Hold it with the gold or silver band on the right. The first bands are digits (black 0 to white 9), the next is the multiplier (how many zeros), and the last is the tolerance. Brown, black, red, gold is 1, 0, × 100 = 1 kΩ ±5%.
Which end do I start from?
Start from the end the bands crowd towards. The tolerance band, usually gold, silver or brown, sits a little apart at the other end.
What's the difference between 4-band and 5-band resistors?
A 4-band resistor gives two digits, enough for ±5% parts. A 5-band resistor gives three, for precise ±1% parts like 4.99 kΩ. The multiplier and tolerance bands work the same way.
What do gold and silver mean in the multiplier band?
Gold multiplies by 0.1 and silver by 0.01, for resistors under 10 Ω. Yellow, violet, gold is 47 × 0.1 = 4.7 Ω.
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