The direct answer for a standard 100k (100,000 ohm) resistor color code is Brown, Black, Yellow for a 4-band resistor, and Brown, Black, Black, Orange for a 5-band resistor. The final band indicates tolerance, typically Gold (±5%) or Brown (±1%). If you are holding a through-hole 100k resistor right now, orient it so the tolerance band (Gold, Silver, or Brown) is on the far right, and read the significant digits from left to right.
The 100k Resistor Color Code Reference Table
Resistor color codes are dictated globally by the IEC 60062 standard. Below is the exact breakdown for identifying a 100k ohm resistor across the two most common through-hole formats.
| Band Position | 4-Band Color (±5%) | 4-Band Meaning | 5-Band Color (±1%) | 5-Band Meaning |
|---|---|---|---|---|
| Band 1 | Brown | 1st Digit: 1 | Brown | 1st Digit: 1 |
| Band 2 | Black | 2nd Digit: 0 | Black | 2nd Digit: 0 |
| Band 3 | Yellow | Multiplier: ×10,000 | Black | 3rd Digit: 0 |
| Band 4 | Gold | Tolerance: ±5% | Orange | Multiplier: ×1,000 |
| Band 5 | N/A | N/A | Brown | Tolerance: ±1% |
Note: 5-band 100k resistors may also feature a Red band (±2%) or a Green band (±0.5%) in the final position, depending on the manufacturer's E-series (E24 vs E96) production run.
Standard Variants and Rows People Get Wrong
A frequent point of confusion on the workbench is mixing up component marking standards with building wiring standards. To be explicitly clear: NEC (NFPA 70) and IEC 60446 do not apply to resistors. Those regional standards dictate building wire and cable jacket colors (e.g., black for hot, green/yellow for earth ground in the EU, green in the US). Resistors use a single, universal global standard: IEC 60062. There is no 'US vs UK' variant for resistor bands; a 100k resistor bought in London has the exact same brown-black-yellow bands as one bought in Chicago.
However, older military-spec components (like MIL-PRF-22684) sometimes used a 'body-tip-dot' painting system rather than bands. If you find a vintage resistor with a brown body, a black tip, and a yellow dot, it is also 100k.
The Rows People Get Wrong
- Confusing Yellow (Band 3) with Orange: On a 4-band resistor, the multiplier band is where most misreads happen. Yellow means ×10,000 (yielding 100k). Orange means ×1,000 (yielding 10k). Under warm bench lighting, a faded orange band can easily look yellow. Always verify with a multimeter if the hue looks ambiguous.
- Reading Backwards: If your first band is Gold or Silver, you are holding the resistor backwards. Gold and Silver are never used as significant digit bands in standard IEC 60062; they are exclusively multipliers (for values under 10 ohms) or tolerance indicators.
- 5-Band Multiplier Shift: Makers transitioning from 4-band to 5-band often forget that the multiplier shifts one band to the right. In a 5-band 100k resistor, the multiplier is Orange (×1,000), not Yellow. If you use Yellow as the multiplier on a 5-band, you will calculate 1,000k (1 Megohm) instead of 100k.
Safe Interpretation When Markings Are Faded or Burnt
When dealing with old equipment where UV exposure, conformal coating, or heat has obscured the paint bands, follow this diagnostic protocol:
- Isolate the Component: Do not trust an in-circuit multimeter reading. Parallel paths through semiconductors and other resistors will skew your measurement. Desolder at least one leg of the resistor, lifting it completely off the PCB pad.
- Measure and Calculate Drift: Measure the isolated component. If it reads 98.5k, it is likely a 100k resistor with a ±5% tolerance that has aged slightly. If it reads 145k, it has suffered thermal damage and must be replaced.
- Check the Schematic or BOM: If the bands are entirely gone, trace the circuit nodes. A 100k resistor is highly common as an I2C pull-up, an op-amp feedback resistor, or a MOSFET gate pull-down. Confirming its role in the circuit topology often confirms its value.
For surface-mount devices (SMD), color codes are abandoned entirely in favor of printed numerals. According to standard SMD resistor coding practices, a 100k SMD resistor will be marked 104 (for 5% tolerance, meaning 10 × 10^4) or 1003 (for 1% tolerance E96 series, meaning 100 × 10^3).
100k Resistor Color Code FAQ
What is the exact SMD equivalent code for a 100k resistor?
For standard 5% tolerance SMD resistors (E24 series), the code is 104. For precision 1% tolerance SMD resistors (E96 series), the code is 1003. If you are working with ultra-small 0201 packages, they are often unmarked entirely, requiring you to rely on your component feeder tape or original packaging for identification.
Can I substitute a 5-band 100k resistor for a 4-band 100k resistor?
Yes, in almost all cases. A 5-band resistor simply indicates a tighter manufacturing tolerance (usually ±1% or ±2%) compared to the 4-band version (±5%). Substituting a tighter tolerance part for a looser one is perfectly safe and often improves circuit stability, particularly in voltage dividers, analog sensor scaling, and timing circuits. The only exception is if the circuit specifically relies on the ±5% drift for a crude compensation mechanism, which is rare in modern design.
Why does my brand new 100k resistor measure 96k on my multimeter?
This is normal and within specification. A standard 4-band 100k resistor with a Gold tolerance band is rated for ±5%. This means the manufacturer guarantees the true resistance will fall anywhere between 95,000 ohms (95k) and 105,000 ohms (105k). If your multimeter reads 96k, the part is well within its acceptable factory variance. If you need it to be exactly 100.0k, you must buy 0.1% precision resistors and hand-select them with a bench meter.
Does the 100k resistor color code change for high-wattage (5W or 10W) resistors?
The IEC 60062 color code rules remain exactly the same regardless of wattage. However, in practice, manufacturers rarely paint color bands on high-wattage wirewound or cement resistors (5W and above). Because these components are physically large, they typically have the value, wattage, and tolerance printed directly onto the ceramic or cement body in plain text (e.g., '100K Ω 5W ±5%').
