The standard 1k resistance color code (1,000 ohms) is Brown, Black, Red, Gold for a 4-band 5% tolerance resistor. For a 5-band 1% precision resistor, the sequence is Brown, Black, Black, Brown, Brown (or Gold for 5% tolerance). Below is the complete breakdown for through-hole and surface-mount formats.
The Complete 1k Ohm Resistor Reference Table
Resistor banding changes depending on the tolerance and the number of bands printed on the body. Use this table to verify your 1k ohm components against the standard IEC color code charts.
| Format | Band 1 (Digit) | Band 2 (Digit) | Band 3 (Digit/Mult) | Band 4 (Mult/Tol) | Band 5 (Tol/Tempco) | Nominal Value |
|---|---|---|---|---|---|---|
| 4-Band (5%) | Brown (1) | Black (0) | Red (×100) | Gold (±5%) | N/A | 1,000 Ω |
| 4-Band (10%) | Brown (1) | Black (0) | Red (×100) | Silver (±10%) | N/A | 1,000 Ω |
| 5-Band (1%) | Brown (1) | Black (0) | Black (0) | Brown (×10) | Brown (±1%) | 1,000 Ω |
| 5-Band (2%) | Brown (1) | Black (0) | Black (0) | Brown (×10) | Red (±2%) | 1,000 Ω |
| 6-Band (1% + Tempco) | Brown (1) | Black (0) | Black (0) | Brown (×10) | Brown (±1%) / Black (250ppm) | 1,000 Ω |
| SMD 3-Digit (EIA) | Printed Code: 102 (10 × 10²) | 1,000 Ω | ||||
| SMD 4-Digit (EIA) | Printed Code: 1001 (100 × 10¹) | 1,000 Ω | ||||
Rows People Get Wrong & Faded Marking Fixes
Even experienced bench technicians misread resistors when the paint is thick, the lighting is poor, or the band spacing is uneven. Here are the most common traps when identifying a 1k resistor and how to resolve them.
The 4-Band vs. 5-Band Multiplier Trap
The most frequent error occurs when reading a 5-band 1% resistor as if it were a 4-band resistor. On a 5-band 1k resistor (Brown-Black-Black-Brown-Brown), the third band is Black (0), acting as the third significant digit. The fourth band is Brown (×10), acting as the multiplier. If you mistakenly treat the third band as the multiplier (like in a 4-band system), you will calculate 10 × 1 = 10 ohms, or you might read the multiplier as Black (×1) and conclude the value is 100 ohms. Always count the total number of bands before assigning multiplier roles.
Red vs. Orange and Brown vs. Red
Manufacturing variations in the epoxy coating can make the Red multiplier band (×100) look distinctly Orange (×1,000) under warm bench lighting. If your 4-band resistor appears to be Brown-Black-Orange, you are looking at a 10k resistor, not a 1k. Similarly, a dark Brown first band can easily be mistaken for Red, which would shift your base value from 10 to 20, resulting in a 2k ohm misidentification.
Never guess the value of a discolored or faded resistor based on visual inspection alone. Overheated carbon film resistors shift in value, often drifting upward by 20% or more before failing open. To safely interpret a faded 1k resistor, desolder one leg to isolate it from the circuit and measure it with a digital multimeter. Never measure resistance in-circuit; parallel traces and semiconductor junctions will create a Thevenin equivalent resistance that yields a falsely low reading on your meter.
Global Standards: IEC 60062 vs. SMD and Legacy Specs
Unlike home wiring, where you must constantly navigate regional differences between NEC (US) and IEC 60446 (EU/UK) color codes, through-hole resistor banding is universally governed by a single global standard: IEC 60062. Whether you buy a Yageo carbon film resistor in Taipei or a Vishay metal film resistor in Germany, the 1k resistance color code remains identical.
However, "regional" or application-specific variants do exist in the broader component ecosystem:
- MIL-PRF-22684 (Military Spec): Older military-grade resistors sometimes feature a 6th band indicating reliability levels (failure rate per 1,000 hours). A 1k resistor with a Yellow 6th band indicates a 0.1% failure rate, while Orange indicates 0.01%. Modern commercial designs rarely use this, but you will encounter it when repairing legacy aerospace or telecom gear.
- EIA-96 SMD Codes: For high-precision 1% surface mount resistors (0603 or 0402 packages), the standard 3-digit "102" code is replaced by the EIA-96 alphanumeric system. A 1k ohm 0603 SMD resistor in EIA-96 is marked as 01C (01 = 100, C = ×10). Always verify the package size and marking style before assuming an SMD part is a standard 5% tolerance.
- Zero-Ohm Jumpers: While not a 1k variant, be aware that a single black band on a through-hole body indicates a 0-ohm jumper wire, not a 1-ohm resistor. This is a common point of confusion for beginners scanning a board with a color code calculator.
Frequently Asked Questions
Can I use a 1k 5% resistor instead of a 1k 1% in my Arduino circuit?
In most hobbyist Arduino and ESP32 applications, yes. A 5% tolerance 1k resistor will measure anywhere between 950 Ω and 1,050 Ω. If you are using it as an LED current-limiting resistor (e.g., dropping 3V at 3mA), a 50-ohm variance is electrically invisible to the human eye. However, if the 1k resistor is part of a voltage divider feeding an ADC (Analog-to-Digital Converter) reference pin, or setting the gain on an op-amp, that 5% variance will introduce measurable errors in your sensor readings. Use 1% metal film resistors for analog signal conditioning and ADC references.
Why does my 1k resistor measure 980 ohms on my multimeter?
This is completely normal and indicates the resistor is functioning exactly as designed. If you are testing a standard 4-band (Gold tolerance) 1k resistor, the manufacturer guarantees the value will fall within ±5% of the nominal 1,000 ohms. 5% of 1,000 is 50, meaning any reading between 950 Ω and 1,050 Ω is a "pass." Furthermore, budget multimeters (like standard $15 clamp meters) often have their own ±1% to ±2% base accuracy error on the resistance range. For bench-accurate readings, use a calibrated 4.5-digit bench meter and ensure your test leads are zeroed out before measuring.
What is the 1k resistance color code for a 6-band resistor?
A 6-band 1k resistor uses the same first five bands as the 5-band version: Brown, Black, Black, Brown, Brown (1-0-0-×10-1%). The 6th band indicates the Temperature Coefficient (Tempco), which tells you how much the resistance drifts as the component heats up. The most common 6th band color for standard 1k metal film resistors is Brown (100 ppm/°C) or Red (50 ppm/°C). If your circuit operates in a high-heat environment (like near a power supply switching MOSFET), pay close attention to this 6th band; a 100 ppm/°C drift means a 50°C temperature rise will shift your 1k resistor by 0.5%, which can detune precision analog filters.
How do I read a 1k surface mount (SMD) resistor without color bands?
SMD resistors use printed numeric codes instead of color bands. For a standard 5% tolerance 1k SMD resistor (usually 0805 or 1206 size), look for the 3-digit code 102. The first two digits (10) are the significant figures, and the third digit (2) is the multiplier (10² or 100). 10 × 100 = 1,000 ohms. For smaller 0402 packages, there is often no marking at all; you must rely on your reel packaging or measure them individually with fine-point tweezers probes connected to your multimeter.
