This calculator reads a resistor's color bands and returns its resistance value, tolerance, and multiplier the moment you select the colors you see — or works the other direction, turning a resistance value like 10kΩ back into the color sequence you'd expect to find. Use it to identify an unmarked or hard-to-read resistor without reaching for a multimeter, or to check which bands to look for before sorting or buying parts.
4-band resistor anatomy: two digit bands, a multiplier, and a tolerance band
How To Read Resistor Color Codes
A standard 4-band resistor encodes its value across four colored bands, each with a fixed job.
Band 1 gives the first digit. Band 2 gives the second digit. Band 3 is the multiplier — how many zeros to add, or what power of ten to multiply by. Band 4 is the tolerance, showing how far the actual resistance can vary from the printed value.
Resistor Color Code Chart
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | — |
| Yellow | 4 | ×10,000 | — |
| Green | 5 | ×100,000 | ±0.5% |
| Blue | 6 | ×1,000,000 | ±0.25% |
| Violet | 7 | ×10,000,000 | ±0.1% |
| Gray | 8 | ×100,000,000 | ±0.05% |
| White | 9 | ×1,000,000,000 | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
Gold and silver are the only two colors that can appear as a multiplier band with a value below ×1 — that's what makes them possible to distinguish from a digit band even without counting band position, since no digit color carries a fractional multiplier.
4 Band Resistor Color Code Calculator
Resistance = (First digit × 10 + Second digit) × Multiplier. The two digit bands form a two-digit number; the third band multiplies it up to the full resistance value.
Example: Red · Red · Brown · Gold = 220Ω ±5%
5 Band Resistor Color Code Calculator
A 5-band resistor uses three digit bands instead of two, giving one extra digit of precision before the multiplier and tolerance bands.
Bands 1 through 3 give three significant digits. Band 4 is the multiplier. Band 5 is the tolerance.
Example: Brown, Black, Black, Brown, Brown. The three digits read 1, 0, 0 — a base value of 100. Brown multiplies by ×10. Resistance = 100 × 10 = 1kΩ ±1%.
Five-band resistors are used wherever a tighter tolerance matters — precision measurement circuits, industrial electronics, and any design where a ±5% error is too loose.
6 Band Resistor Color Code Calculator
A 6-band resistor adds a sixth band on top of the standard 5-band sequence: temperature coefficient, measured in parts per million per degree Celsius (ppm/°C). It shows how much the resistance drifts as temperature changes — a lower ppm/°C value means a more temperature-stable resistor.
Six-band resistors show up in precision analog circuits and instrumentation, where resistance drift across a temperature range would otherwise throw off a measurement.
Resistor Color Code Formula
Resistance is always digits multiplied by the multiplier band: Digits × Multiplier = Resistance.
To analyze the relationship between your decoded resistance, circuit voltage, and current flow, verify the parameters using our core Ohm's Law Calculator (Homepage).
The tolerance band sets the acceptable range around that calculated value — it doesn't change the resistance itself, only how far the real, manufactured resistor is allowed to drift from the printed number.
Tolerance Colors at a Glance
Tighter tolerance costs more and matters most in precision circuits — voltage references, measurement dividers, filter networks — where a few percent of resistance error changes the circuit's actual behavior.
Resistor Color Code Converter
The calculator above works in both directions: colors to resistance, or resistance to colors.
Color to resistance: Yellow, Violet, Brown, Gold. Yellow = 4, Violet = 7, giving 47. Brown multiplies by ×10. Resistance = 47 × 10 = 470Ω ±5%.
Resistance to color: entering 10,000Ω returns Brown, Black, Orange, plus a tolerance band of your choice depending on the actual part.
Reverse Resistor Color Code Calculator
Enter the resistance value you need, and the calculator returns the matching band sequence — the reverse of reading an existing resistor, useful when you know the value you want but need to identify the right part in a parts bin or on a supplier's site.
The result includes the resistance value, the color sequence, and the available tolerance options for that value, since most resistance values are stocked in more than one tolerance grade.
Resistor Color Code Calculator for Different Resistor Types
The color band system applies across several physical resistor constructions, not just one. Axial through-hole resistors, film resistors, and MELF resistors all use the same band-reading rules described above — the physical build changes, the color code logic doesn't.
Carbon Film
Most common general-purpose type. Typically ±5% tolerance. Standard in hobby electronics where precision isn't critical.
Metal Film
Higher accuracy, lower noise, better stability. Commonly ±1% tolerance. Used where precision matters more than cost.
Wire Wound
Higher power dissipation. Coiled wire adds inductance — poor choice for high-frequency AC despite power advantages.
MELF
Metal Electrode Leadless Face. Cylindrical SMD form but retains color-band marking. Used in precision, high-reliability circuits.
SMD Resistor Color Code Calculator
No, standard SMD resistors do not use color bands. Flat surface-mount chip resistors are too small for a color band system to work reliably, so they use a printed numeric code instead — typically three or four digits, or an EIA-96 code on very small precision parts.
The numeric system follows the same digit-plus-multiplier logic as color bands, just written as numbers instead of colors.
SMD Resistor Code Calculator
103 reads as digits 1 and 0, multiplied by 10³: (10) × 1,000 = 10kΩ.
472 reads as digits 4 and 7, multiplied by 10²: (47) × 100 = 4.7kΩ.
Since this is a genuinely separate coding system rather than a color-band variant, a full SMD code lookup belongs on its own dedicated calculator page — this section exists to answer the question, not to replace that tool.
Common Resistor Color Code Calculations
| Resistance | Color Bands |
|---|---|
| 10Ω | Brown, Black, Black |
| 22Ω | Red, Red, Black |
| 47Ω | Yellow, Violet, Black |
| 100Ω | Brown, Black, Brown |
| 220Ω | Red, Red, Brown |
| 330Ω | Orange, Orange, Brown |
| 470Ω | Yellow, Violet, Brown |
| 1kΩ | Brown, Black, Red |
| 2.2kΩ | Red, Red, Red |
| 4.7kΩ | Yellow, Violet, Red |
| 10kΩ | Brown, Black, Orange |
| 22kΩ | Red, Red, Orange |
| 47kΩ | Yellow, Violet, Orange |
| 100kΩ | Brown, Black, Yellow |
| 470kΩ | Yellow, Violet, Yellow |
| 1MΩ | Brown, Black, Green |
All values shown as the three core bands — add a fourth band (commonly Gold, ±5%) for the complete real-world code.
Resistor Color Code for Arduino Projects
Reading resistor values correctly matters constantly in Arduino work — LED current-limiting resistors, pull-up and pull-down resistors on digital pins, and the resistor pairs used in sensor voltage dividers all depend on picking (and correctly identifying) the right value.
Misreading a color band on an LED resistor is one of the most common sources of a dead LED or an overdriven pin in beginner projects — worth double-checking against this calculator, or a multimeter, before powering up a new build.
Resistor Basics: What a Resistor Does
A resistor limits current flow in a circuit by a fixed amount, measured in ohms (Ω). The higher the resistance, the more it restricts current for a given voltage — the exact relationship described by Ohm's Law.
Resistors don't care about current direction, and unlike capacitors or inductors, their behavior doesn't change with signal frequency (aside from minor real-world parasitic effects at very high frequencies) — a resistor's job is the same in a DC circuit as in an AC one.
Resistor Color Code and Ohm's Law
The color code identifies R — the resistance value Ohm's Law needs as an input. Ohm's Law itself, V = I × R, only becomes usable once you know the actual resistance in the circuit, and reading the color bands is how that number gets determined without a multimeter. That same R value is exactly what feeds into a voltage divider calculation or an Ohm's Law calculation — reading the bands correctly here is the first step before either of those formulas produces a trustworthy result.
Resistor Circuit Symbols
Two standard schematic symbols represent a resistor, depending on which convention a diagram follows. The American/ANSI standard uses a zigzag line. The IEC/European standard uses a plain rectangle.
Both symbols represent the identical component — the difference is purely regional schematic convention, not a difference in the resistor itself.
Resistor Color Code Applications in Electronics
Reading color codes correctly matters anywhere a resistor's exact value affects circuit behavior, including:
- Selecting the correct LED current-limiting resistor before powering a circuit
- Verifying a voltage divider's resistor pair before relying on its output voltage
- Sorting and identifying loose or unmarked resistors from a parts bin
- Confirming a replacement part matches the original before a repair
- Checking bias resistors in amplifier and transistor circuits
Troubleshooting Resistor Color Code Reading
Not sure which end to start reading from?
The tolerance band — usually gold or silver — sits slightly separated from the other bands and is always read last. Start from the opposite end, furthest from that gap.
Can't tell orange from red, or blue from violet?
Poor lighting is the most common cause of misreading adjacent colors on the spectrum. When a reading looks uncertain, a multimeter measurement settles it faster than trying to improve the lighting.
Bands worn, faded, or dirty?
Don't guess — a resistor with unreadable bands should be measured directly rather than assumed, since a printed color code that can't be read confidently isn't reliable information.
Resistor Color Code Limitations
Color code reading has real limits worth knowing before relying on it completely.
Human color perception varies, and colorblindness affects a meaningful share of readers — orange/brown and blue/violet are common confusion pairs. The tolerance band only guarantees a range, not the exact value; two resistors both marked 1kΩ ±5% can measure anywhere from 950Ω to 1,050Ω and both be correct. And the printed code reflects the manufacturer's intended value at production, not the resistor's current actual resistance — a multimeter reading is always the ground truth over the printed bands, especially on an old or physically stressed component.