Resistor Color Code Calculator
Select the color bands on a 4-band or 5-band resistor to decode its value and tolerance. Instant result with visual band preview and full reference table.
Last updated: May 2026
Select all band colors to decode the resistor value.
4-band: digit · digit · multiplier · tolerance | 5-band: digit · digit · digit · multiplier · tolerance
Full color code reference
| Color | Digit value | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 Ω | - |
| Brown | 1 | ×10 Ω | ±1% |
| Red | 2 | ×100 Ω | ±2% |
| Orange | 3 | ×1 kΩ | - |
| Yellow | 4 | ×10 kΩ | - |
| Green | 5 | ×100 kΩ | ±0.5% |
| Blue | 6 | ×1 MΩ | ±0.25% |
| Violet | 7 | - | ±0.1% |
| Grey | 8 | - | ±0.05% |
| White | 9 | - | - |
| Gold | - | ×0.1 Ω | ±5% |
| Silver | - | ×0.01 Ω | ±10% |
| None | - | - | ±20% |
How to read a resistor
- Hold the resistor so the gold or silver tolerance band is on the right. Read left to right.
- 4-band: band 1 = first digit, band 2 = second digit, band 3 = multiplier, band 4 = tolerance.
- 5-band (precision, 1% or better): band 1-3 = three digits, band 4 = multiplier, band 5 = tolerance.
- If you can't tell which end to start from: gold/silver is always the tolerance band at the right.
Turning a band pattern into a value you can use
Decoding the bands is the identification step. Once you have a resistance value, that number feeds directly into the calculators that follow it in the build sequence:
- Start upstream: the base electrical relationships. The Ohm's Law calculator gives you the resistance a circuit needs. Come here when you are pulling a resistor from the bin to match that target.
- Before this: size the resistor for an LED. The LED series resistor calculator tells you the ohm value to look for. Use this decoder to confirm the part in your hand matches that value.
- Or before this: set a voltage divider ratio. The voltage divider calculator gives you R1 and R2. Decode the bands on your candidate parts here before committing them to the circuit.
- You are here: decode a resistor from its bands. Select the colors left to right, tolerance band last. The result is the nominal value and the tolerance range the manufacturer guarantees. Start from the end that has a wider gap or a gold or silver band, that end holds the tolerance stripe and sets the reading direction.
- Decode the other passive: capacitors use a printed code. The capacitor code calculator does the same job for capacitors marked with a 3-digit number rather than color bands.
- Check the supply can deliver the current. Feed the decoded resistance value into the watts, volts and amps calculator to confirm the rail current and power budget.
- Watch the wire on a long run. On a 12 V or LED-strip run, resistance adds up over distance. The voltage drop calculator sizes the cable so the far end still sees adequate voltage.
For AC circuits, resistance gives way to reactance. The impedance calculator and the capacitor and inductor reactance tools handle those cases.
Frequently Asked Questions
How do I tell a 4-band resistor from a 5-band?
Count the colored bands; 4-band resistors have four stripes, 5-band have five. 5-band components are typically precision (1% or better tolerance) and are slightly more expensive. If a resistor has a brown, red or grey tolerance band (not gold or silver), it is very likely a 5-band. In the part bin, 4-band gold tolerance resistors are the most common type.
The bands are hard to read: how do I measure it instead?
Set your multimeter to resistance (Ω) mode, touch the probes to each leg and read the value directly. This is more reliable than trying to identify faded or ambiguous colors, especially for very small resistors (0402, 0603 SMD). For SMD components, the value is usually printed as a 3- or 4-digit code directly on the part.
What does a resistor with only three bands mean?
Three-band resistors are treated as 4-band with an implied gold (±5%) tolerance. The third band is the multiplier. They are older and less common today. Two-band resistors do not exist in standard IEC coding; if you see two stripes, it is likely a diode or inductor, not a resistor.
How do I orient a resistor when both ends look equally spaced?
On a 4-band resistor with an ambiguous spacing, look for gold or silver: those colors never appear as digit bands (only as multipliers for sub-ohm values, which are rare), so a gold or silver stripe almost always marks the tolerance end. Start reading from the opposite end. On a 5-band part, the tolerance band is often a different width or has a visibly larger gap from band 4. When the spacing is genuinely unclear, measure it with a multimeter set to resistance mode and compare the result to both possible readings from this decoder: one will be a recognizable E12 or E24 value and the other will not. If neither matches a standard value, the bands may be faded or the component may not be a standard resistor.
Methodology and sources
This tool decodes a resistor's printed color bands into its nominal resistance, tolerance and value range, following the standard color-coding scheme for 4-band and 5-band axial resistors.
- Method: 4-band value = (digit1 × 10 + digit2) × multiplier; 5-band value = (digit1 × 100 + digit2 × 10 + digit3) × multiplier. The tolerance band sets the range as value × (1 ± tolerance / 100), so the displayed low and high are value × (1 − tol / 100) and value × (1 + tol / 100).
- Standards and sources: IEC 60062 (marking codes for resistors and capacitors), which defines the digit colors (black 0 through white 9), the multiplier colors (including gold ×0.1 and silver ×0.01) and the tolerance bands (for example brown ±1%, gold ±5%, silver ±10%, none ±20%). The arithmetic is exact decimal math.
- Assumptions and limits: The tool assumes the bands are read in the correct direction, with the gold or silver tolerance band on the right. Faded, ambiguous or non-standard markings can be misread, and very small SMD parts use a printed numeric code instead of bands. When a value matters, confirm it with a multimeter or the component datasheet.
Reviewed and maintained by Rick Oosterling, who builds and wires 12 V, solar and EV systems hands-on. Last reviewed: June 2026. This decoder is a reading aid, not a substitute for measuring the part with a multimeter or checking the manufacturer's datasheet before you rely on a value in a circuit.
Next step in this workflow
Value confirmed: plug it into Ohm's Law to complete your circuit calculation.