Resistor Color Code Calculator
Pick the four band colors to read the resistance value, tolerance and min/max range of any 4-band resistor.
Open calculatorLast updated: 2026-09-15
How the calculation works
- Bands 1 and 2 give two significant digits; band 3 multiplies by a power of ten (gold = 0.1, silver = 0.01).
- Band 4 sets tolerance, which defines the guaranteed min/max range.
- Read bands from the end where they cluster nearest — the tolerance band (gold/silver) sits at the far end.
Worked example
Interpreting the result
The tolerance band tells you how much the real part can differ from its marking — critical when a circuit needs 1% parts. If a resistor measures outside its color-coded range, it's damaged or misread (check the orientation).
Assumptions
- 4-band axial through-hole resistors (EIA color code).
- Reading direction from the clustered end.
Limitations
- 5-band precision and 6-band (with temperature coefficient) resistors need their own charts.
- SMD resistors use numeric codes (e.g. 103 = 10 kΩ) — not covered here.
Colour code: digits, multipliers and tolerances
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | × 1 | — |
| Brown | 1 | × 10 | ± 1 % |
| Red | 2 | × 100 | ± 2 % |
| Orange | 3 | × 1 k | — |
| Yellow | 4 | × 10 k | — |
| Green | 5 | × 100 k | ± 0.5 % |
| Blue | 6 | × 1 M | ± 0.25 % |
| Violet | 7 | × 10 M | ± 0.1 % |
| Grey | 8 | — | ± 0.05 % |
| White | 9 | — | — |
| Gold | — | × 0.1 | ± 5 % |
| Silver | — | × 0.01 | ± 10 % |
This is the standard four-band code. The calculator accepts the multipliers and tolerances most 4-band resistors use.
Worked examples (calculated)
| Bands (digit, digit, multiplier, tolerance) | Resistance | Guaranteed range |
|---|---|---|
| brown, black, red, gold | 1 kΩ | 950 Ω to 1.05 kΩ |
| red, red, brown, gold | 220 Ω | 209 Ω to 231 Ω |
| yellow, violet, red, gold | 4.7 kΩ | 4.46 kΩ to 4.93 kΩ |
| orange, orange, orange, gold | 33 kΩ | 31.4 kΩ to 34.6 kΩ |
| green, blue, yellow, silver | 560 kΩ | 504 kΩ to 616 kΩ |
| brown, black, black, gold | 10 Ω | 9.5 Ω to 10.5 Ω |
Preferred values: the E12 and E24 series (one decade)
Resistors are made in a limited set of values. Multiply these by 1, 10, 100… to get the values you can buy.
| Series | Values | Typical tolerance |
|---|---|---|
| E12 | 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2 | ± 10 % |
| E24 | 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, 9.1 | ± 5 % |
How to read a 4-band resistor
- Turn the resistor so the tolerance band (usually gold or silver, set slightly apart from the others) is on the right.
- Read the first two bands as digits, the third as the multiplier, the fourth as the tolerance.
- Example: yellow, violet, red, gold is 4 7 × 100 = 4,700 Ω, or 4.7 kΩ, within ± 5 %.
- When the bands are hard to tell apart, measure with a multimeter with the resistor out of circuit.
Why only certain values exist
The E-series spread values so that neighbours overlap within their tolerance. A ± 5 % resistor from the E24 series covers the whole range without gaps, which is why 4.7 kΩ exists and 4.5 kΩ usually does not. When a design needs a value in between, use two standard resistors in series or parallel.
Frequently asked questions
Which end do I start reading from?
From the end where the bands are closest together. The gold or silver tolerance band always goes last.
What does a gold multiplier band mean?
Multiply by 0.1 — used for sub-1-Ω values like 4.7 Ω (yellow-violet-gold-gold).