The 500 ohm resistor colour code is Green-Black-Brown-Gold for standard 4-band (5% tolerance) components, and Green-Black-Black-Black-Brown for precision 5-band (1% tolerance) components. However, before you dig through your component bins, you need to know a critical bench reality: 500 Ω is not a standard E24 (5%) value. It is an E96 (1%) value. If you are looking for a 500 Ω resistor in a standard 5% hobby kit, you will not find it—the closest standard values are 470 Ω and 510 Ω.

The 500 Ohm Resistor Colour Code Reference Table

Below is the exact band breakdown for both common through-hole formats. Read the bands from left to right, keeping the tolerance band (usually Gold, Silver, or Brown) spaced slightly apart on the far right.

Format Band 1 (1st Digit) Band 2 (2nd Digit) Band 3 (3rd Digit / Multiplier) Band 4 (Multiplier / Tolerance) Band 5 (Tolerance) Calculated Value
4-Band (5%) Green (5) Black (0) Brown (×10) Gold (±5%) N/A 50 × 10 = 500 Ω
5-Band (1%) Green (5) Black (0) Black (0) Black (×1) Brown (±1%) 500 × 1 = 500 Ω
The E-Series Reality Check: Standard 5% carbon and metal film resistors follow the IEC 60063 E24 series, which includes 470 Ω and 510 Ω, but skips 500 Ω. If your circuit schematic calls for exactly 500 Ω, you must source a 1% tolerance (E96 series) metal film resistor, or use a precision trimmer potentiometer.

Decoding the Bands and the "Rows People Get Wrong"

The math behind the colour code is straightforward: significant digits followed by a decimal multiplier. For the 4-band 500 Ω resistor, Green (5) and Black (0) give us 50. The Brown multiplier means "add one zero" (×10), yielding 500. For the 5-band version, Green-Black-Black gives 500, and the Black multiplier means "add no zeros" (×1).

Despite the simple math, misreads happen constantly on the bench. Here are the specific rows and patterns people get wrong:

  • Brown vs. Red Multiplier Confusion: Brown is ×10, Red is ×100. If you mistakenly read the 4-band multiplier as Red, you will calculate 5,000 Ω (5 kΩ). Always verify the multiplier band under bright, neutral-white light; cheap carbon film resistors often have a muddy red-brown hue.
  • Reading Direction (The Gold/Silver Anchor):strong> Gold and Silver are never used as significant digits (the first two or three bands). They are exclusively multipliers or tolerance indicators. If your first band looks Gold or Silver, you are reading the resistor backwards.
  • The 5-Band Black Multiplier Trap: In a 5-band resistor, a Black fourth band means a multiplier of ×1 (10^0). Beginners often assume Black means "zero" and multiply the value by zero, or they skip it entirely. Black in the multiplier position simply means "keep the significant digits exactly as they are."

Global Standards vs. Format Variants (IEC 60062)

Unlike mains wiring colour codes—which vary wildly between the US NEC, European IEC, and old UK BS 7671 standards—resistor colour codes are universally standardized. There is no "US version" or "European version" of a resistor colour code.

The global authority is IEC 60062, which dictates the exact chromaticity and luminance for each band. What does vary is the format based on the component's tolerance and physical package:

Format Variant Standard / Tolerance When You Will See It
4-Band IEC 60062 / ±5% (Gold) or ±10% (Silver) General purpose through-hole, older carbon composition, basic hobby kits.
5-Band IEC 60062 / ±1% (Brown) or ±2% (Red) Modern metal film, precision analog circuits, audio crossovers, E96 values (like 500 Ω).
6-Band IEC 60062 + Temperature Coefficient (TCR) High-precision instrumentation. The 6th band (often 100ppm/°C) indicates how much the value drifts with heat.
SMD (Surface Mount) EIA-96 or 3/4-digit printing PCB assembly. A 500 Ω SMD resistor will simply be printed with "501" (50 × 10^1) or "5000" depending on the size.

Faded, Burnt, or Missing Markings: Safe Interpretation

When a resistor has been subjected to thermal stress, the epoxy coating darkens, and the colour bands turn into indistinguishable brown smudges. Carbon composition resistors are particularly prone to this, and their resistance value actually drifts upward when overheated due to the breakdown of the carbon binder.

If you are troubleshooting a board with faded markings, follow this safe interpretation protocol:

  1. Isolate the Component: Do not measure a resistor while it is still soldered into the circuit. Parallel paths through ICs and other components will give you a falsely low reading. Desolder at least one leg.
  2. Measure with a DMM: Use a digital multimeter on the appropriate ohms range. If the reading is between 490 Ω and 510 Ω, it is almost certainly a 500 Ω (1%) or 510 Ω (5%) resistor that has drifted slightly.
  3. Check for Physical Damage: If the resistor body is cracked, blistered, or measures open-loop (OL), the internal element has failed. Do not trust the faded colour bands to order a replacement. The heat that destroyed the resistor may have altered the paint colours.
  4. Reverse-Engineer the Circuit: If the value is illegible and the part is burnt, look at the surrounding components. If it is an LED current limiter on a 5V logic line, a standard 470 Ω or 510 Ω is the safe, mathematically sound replacement.
Bench Trick: If a colour code is too faded to read but the resistor measures perfectly at 500.4 Ω, it is a 1% metal film resistor. Standard 5% carbon films rarely hold a value that tight after years of thermal cycling.

Decision Path: Which 500R Resistor Should You Actually Buy?

Stop guessing in the parts aisle. Use this decision matrix to terminate your search and buy the exact right component for your application. For a deeper look at standard preferred values, refer to the All About Circuits resistor guide.

Your Application Scenario Required Precision Concrete Pick & Part Number
LED current limiting, digital pull-ups, basic prototyping 5% (E24 Series) Buy 510 Ω. 500 Ω is not in the 5% kit. 510 Ω is the standard E24 equivalent. Pick any standard 1/4W 510R metal film.
Audio crossovers, DAC reference networks, analog sensor biasing 1% (E96 Series) Buy exact 500 Ω (1%). Vishay MRS25000C5000FRP00 (1/4W, 1%, 50ppm) or Yageo MFR-25FRF52-500R.
High-power load testing, dummy loads, power supply bleeder 5% or 10%, High Wattage Buy 500 Ω Wirewound (5W+). Look for a ceramic-cased wirewound like the Vishay AC05000005009JA500. Colour codes do not apply here; values are printed.
Repairing vintage equipment where original BOM specified 500R Match Original Buy 500 Ω 1/2W Carbon Film. Xicon 291-500-RC. (Note: Carbon film is preferred in vintage audio to match original noise profiles).

Final Recommendation: If you are a hobbyist building digital or basic analog circuits, close the 500 Ω datasheet and order 510 Ω 1/4W 1% Metal Film resistors. They are universally available, cost fractions of a cent, and the 2% difference in resistance is entirely absorbed by the tolerance margins of standard LEDs, transistors, and logic ICs. Only hunt down exact 500 Ω (1%) resistors when you are actively designing precision measurement front-ends or repairing calibrated analog instrumentation.