The colour resistor chart translates the painted bands on axial resistors into exact ohmic values, tolerances, and temperature coefficients. Based on the international IEC 60062 standard (historically EIA RS-279), the direct answer for reading any resistor is to identify the band count: 4-band for general-purpose carbon film (two significant digits), 5-band for precision metal film (three significant digits), and 6-band for high-stability analog applications (adds a temperature coefficient band). Always read from left to right, keeping the tolerance band (usually gold or silver) on the far right.
The Master Colour Resistor Chart (IEC 60062)
How to read this table: This chart covers all standard axial through-hole resistors. The Digit column applies to the first two bands (4-band) or first three bands (5/6-band). The Multiplier column applies to the third band (4-band) or fourth band (5/6-band). The Tolerance column is always the last band on a 4/5-band resistor, or the second-to-last on a 6-band. The Temp. Coeff. column applies exclusively to the 6th band on 6-band resistors. Letter codes in parentheses (e.g., F, J) are the standard EIA marking equivalents often found on SMD components and datasheets.
| Colour | Digit Value (Sig. Figs) | Multiplier | Tolerance | Temp. Coeff. (ppm/°C) |
|---|---|---|---|---|
| Black | 0 | ×1 (100) | — | 250 (U) |
| Brown | 1 | ×10 (101) | ±1% (F) | 100 (S) |
| Red | 2 | ×100 (102) | ±2% (G) | 50 (R) |
| Orange | 3 | ×1k (103) | — | 15 (P) |
| Yellow | 4 | ×10k (104) | — | 25 (Q) |
| Green | 5 | ×100k (105) | ±0.5% (D) | 20 (Z) |
| Blue | 6 | ×1M (106) | ±0.25% (C) | 10 (M) |
| Violet | 7 | ×10M (107) | ±0.1% (B) | 5 (K) |
| Grey | 8 | ×100M (108) | ±0.05% (A) | — |
| White | 9 | ×1G (109) | — | — |
| Gold | — | ×0.1 (10-1) | ±5% (J) | — |
| Silver | — | ×0.01 (10-2) | ±10% (K) | — |
Source: IEC 60062:2016 / EIA RS-279. For deeper standard documentation, refer to the All About Circuits resistor reference or Electronics Tutorials.
Derating, Tolerances, and What the Chart Cannot Tell You
Knowing the nominal value is only half the battle on the bench. Here is how environmental factors modify that base number, and where the colour code falls short.
Which Column Applies to Your Installation?
If you are building a basic LED indicator or a pull-up network, the 4-band column (carbon or thick film, ±5% tolerance) is all you need. If you are designing an op-amp feedback loop, an audio crossover, or an ADC voltage divider, you must use the 5-band column (metal film, ±1% or better) to prevent gain drift. The 6-band column is reserved for precision measurement equipment and RF oscillators where ambient temperature swings will detune the circuit.
How Derating Modifies the Base Value
The 6th band (Temperature Coefficient, or "tempco") tells you how many parts per million (ppm) the resistance shifts for every degree Celsius above the standard 20°C ambient.
Drift = 50°C × 50 ppm = 2,500 ppm (or 0.25%).
0.25% of 10,000Ω is 25Ω. Your resistor is now nominally 10,025Ω. In a high-gain transimpedance amplifier, this 25Ω shift can introduce measurable DC offset errors.
Beyond tempco, remember power derating. A standard 1/4W (0.25W) resistor is only rated for 0.25W at 70°C. If your enclosure hits 100°C, the manufacturer's derating curve typically forces you to treat it as a 1/8W (0.125W) part to prevent the lacquer coating from charring.
What the Table Cannot Tell You
- Power Rating (Wattage): The colour bands dictate ohms, not watts. A 1/4W and a 1/2W metal film resistor can have the exact same colour bands. You must identify wattage by physical size (e.g., a standard 1/4W body is roughly 6.3mm long; a 1/2W is 9.0mm).
- Parasitic Inductance and Capacitance: The chart won't tell you if a resistor is wirewound. Wirewound resistors act like small inductors at high frequencies, making them useless for RF snubbers despite having the correct ohmic value.
- Voltage Coefficient: In high-voltage applications (e.g., >500V across a single thick-film resistor), the resistance value physically drops as the applied voltage increases. The colour code assumes low-voltage linear operation.
Bench Tips for Reading Faded or Burnt Resistors
When a resistor overheats, the epoxy coating blisters and the paint turns a uniform charred brown or black. Before you scrap the board:
- Look at the leads: The paint near the wire leads often survives the heat. Use a 10x loupe to check the base colour near the metal caps.
- Measure in-circuit (with caution): Power off the board, discharge all filter capacitors, and measure across the resistor. If you read 11.8kΩ on a board where a 10kΩ 5% resistor is expected, the resistor is likely fine (10k + 5% = 10.5k max, but parallel circuit paths can lower the reading, or it may have drifted slightly). If you read open (OL), it is blown.
- Desolder one leg: To get a true reading of a suspect component, lift one leg from the pad to isolate it from parallel silicon paths, then measure.
Colour Resistor Chart FAQ
Why does my colour resistor chart show gold and silver in the multiplier column?
Gold and silver in the multiplier position represent fractional values. A gold multiplier means "divide by 10" (×0.1), and silver means "divide by 100" (×0.01). For example, a 4-band resistor with Yellow, Violet, Gold, Gold bands reads as 4, 7, ×0.1, ±5%. This equals 4.7Ω with a 5% tolerance. These are very common in current-sense shunt resistors.
How do I tell the difference between a 4-band and 5-band resistor just by looking?
Look at the body colour and the band spacing. 4-band resistors are typically carbon film with a tan or beige body. 5-band resistors are usually metal film with a distinct blue, red, or dark green body. Furthermore, on a 5-band resistor, the first three bands are grouped tightly together on the left, with a noticeable gap before the multiplier and tolerance bands on the right.
Is there a colour code for surface mount (SMD) resistors?
No. SMD resistors are too small for painted bands. Instead, they use the EIA-96 numbering system or standard 3-digit/4-digit printed codes. A 3-digit code like "103" means 10 × 103 (10kΩ). A 4-digit code like "1002" means 100 × 102 (10kΩ, 1% tolerance). The underlying mathematical logic (significant digits + multiplier) is identical to the colour chart.
What happens if I read the bands backwards?
Reading backwards will yield a nonsensical or wildly incorrect value. To ensure you are reading left-to-right correctly: first, locate the tolerance band. Gold (±5%) and Silver (±10%) are almost never used as the first significant digit band, so if you see gold or silver, that is your right-hand side. Second, the first band is typically printed slightly closer to the physical wire lead than the tolerance band is to the opposite lead.
