How do I read a 4-band resistor?

Hold the resistor so the tolerance band (Gold or Silver) is on the right. The remaining three bands on the left are read in order: the first two are significant digits (0–9), and the third is a multiplier. Multiply the two-digit number by the multiplier to get the resistance in ohms. For example, Brown-Black-Red-Gold = 10 × 100 = 1,000 Ω = 1 kΩ ±5%.

What is the difference between a 4-band and a 5-band resistor?

A 4-band resistor encodes 2 significant digits (D1, D2) plus a multiplier and tolerance — sufficient for ±5% or ±10% components. A 5-band resistor adds a third significant digit (D1, D2, D3) before the multiplier, allowing tighter tolerance values like ±1% or ±2% to be read more precisely. 5-band resistors are common in high-precision applications such as audio circuits, measurement equipment, and calibrated references.

What does a 6-band resistor's extra band mean?

The 6th band on a precision resistor indicates its temperature coefficient (tempco), expressed in parts per million per Kelvin (ppm/K). It specifies how much the resistance changes for every 1°C rise in temperature. A Brown 6th band means 100 ppm/K — the resistance shifts by 100 ppm (0.01%) per degree. Lower ppm/K values mean greater temperature stability. 6-band resistors are used in precision analog circuits, sensor bridges, reference voltage dividers, and industrial measurement systems where resistance drift would introduce measurement error.

What are the E-series resistor standard values?

Resistors are manufactured in preferred value series defined by IEC 60063: E6 (±20%), E12 (±10%), E24 (±5%), E48 (±2%), E96 (±1%), and E192 (±0.5%). Each series defines the number of resistor values per decade — E12 has 12 values, E96 has 96. Standard E24 values include 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, and 9.1 (×any power of 10). Always choose a value from the appropriate series for your tolerance.

Can I use this tool for SMD resistors?

SMD (surface-mount) resistors use a 3- or 4-digit numeric code instead of color bands. The 3-digit code encodes 2 significant digits and a multiplier exponent: '472' means 47 × 10² = 4,700 Ω. The 4-digit code adds one extra significant digit. Use the Value → Color mode of this calculator to confirm your target resistance, then apply the SMD numbering convention separately. EIA-96 coded SMD resistors use a 2-digit code plus a letter multiplier, which requires a separate EIA-96 lookup table.

What do Gold and Silver bands mean on a resistor?

Gold and Silver have two distinct meanings depending on their position. As a multiplier band (3rd band in 4-band, 4th in 5-band), Gold means ×0.1 and Silver means ×0.01, used for sub-ohm resistors like 0.47 Ω (Yellow-Violet-Gold). As a tolerance band (last band), Gold means ±5% and Silver means ±10%. Resistors with no tolerance band at all are ±20%. Gold and Silver never appear as significant digit bands.

Why does my resistor measure differently from the color code?

A small deviation is expected — the tolerance band tells you the allowed manufacturing spread. A 1 kΩ ±5% Gold resistor can legally measure anywhere from 950 Ω to 1,050 Ω. Additional factors that can shift a reading: component self-heating (resistance rises with power dissipation), temperature coefficient drift (especially significant for 6-band precision types at elevated temperatures), contact resistance in your probe leads (typically 0.1–0.5 Ω), and component aging. For critical measurements, measure at room temperature with a 4-wire Kelvin connection to eliminate lead resistance.

What colors can appear on each band position?

Significant digit bands (D1–D3) can be any of Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, or White (0–9). Multiplier bands add Gold (×0.1) and Silver (×0.01) to the ten digit colors. Tolerance bands use Brown (±1%), Red (±2%), Green (±0.5%), Blue (±0.25%), Violet (±0.1%), Gray (±0.05%), Gold (±5%), Silver (±10%), and no band (±20%). Temperature coefficient bands (6th band only) are Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, or Gray, mapping to 250, 100, 50, 15, 25, 20, 10, 5, and 1 ppm/K respectively.

Resistor Color Code Calculator – 4/5/6-Band Decode & Encode Online

Decode resistor color bands to resistance values or encode a resistance value into color bands. Supports 4, 5, and 6-band resistors with tolerance and temperature coefficient. Free online resistor calculator.

Band Count

Select Band Colors

Multiplier

Tolerance

Result

1 kΩ

±5%

Click to copy

Resistor Color Code Calculator — 4, 5, and 6-Band Decode & Encode

A resistor color code is the system of colored bands printed on through-hole resistors to indicate their resistance value, manufacturing tolerance, and — for precision types — temperature coefficient. Defined by the IEC 60062 standard, each color maps to a specific digit (0–9), a power-of-ten multiplier, a tolerance percentage, or a temperature coefficient in ppm/K. Learning to read resistor bands quickly is a fundamental skill for electronics engineers, makers, students, and anyone working with analog or mixed-signal circuits.

This free online resistor color code calculator works in both directions. In Color → Value mode, select the color of each band to instantly see the decoded resistance, tolerance, and temperature coefficient. In Value → Color mode, enter a target resistance in Ω, kΩ, MΩ, or GΩ and choose the number of bands — the calculator shows which colors represent that value. Both modes include a live SVG resistor diagram that updates as you make selections, and the result can be copied to clipboard with a single click. Settings are preserved between sessions.

The calculator supports all three common resistor formats: 4-band (2 significant digits, used for ±5%–±20% general-purpose resistors), 5-band (3 significant digits, used for ±1%–±2% precision resistors), and 6-band (3 digits + multiplier + tolerance + temperature coefficient, used for high-stability precision components in measurement, audio, and reference circuits).

Band Positions and What Each Band Encodes

Each band position on a resistor body has a strictly defined role. The number of bands determines how many significant digits the value uses and whether temperature stability information is included.

4-Band: D1, D2, Multiplier, Tolerance
Example: Brown-Black-Orange-Gold = 10 × 1 kΩ = 10 kΩ ±5%

5-Band: D1, D2, D3, Multiplier, Tolerance
Example: Red-Red-Black-Black-Brown = 220 × 1 = 220 Ω ±1%

6-Band: D1, D2, D3, Multiplier, Tolerance, Temp. Coeff.
Example: Brown-Black-Black-Brown-Brown-Brown = 100 × 10 = 1 kΩ ±1% 100 ppm/K

Significant Digit Bands (D1–D3)

The first two or three bands encode the numeric mantissa of the resistance value. Each band is a digit from 0 (Black) to 9 (White). The first band is never Black in practice — a black first band would mean the resistor value starts with 0, which manufacturers avoid. The digit bands can only be one of the ten colors from Black to White; Gold and Silver are not valid digit band colors.

Multiplier Band

The multiplier band scales the digit value by a power of ten. Black means ×1, Brown ×10, Red ×100, up to White for ×1 GΩ. Gold (×0.1) and Silver (×0.01) extend the range below 1 Ω, used for precision current-sensing and low-impedance load resistors. The formula is: Resistance = (D1×10 + D2) × Multiplier for 4-band, or (D1×100 + D2×10 + D3) × Multiplier for 5- and 6-band.

Tolerance Band

The tolerance band — always the rightmost band and often Gold or Silver — defines the manufacturing precision as a percentage of the nominal value. A ±5% (Gold) 10 kΩ resistor can legally measure 9,500–10,500 Ω. For precision applications, Brown (±1%) and Red (±2%) are common; Green (±0.5%), Blue (±0.25%), Violet (±0.1%), and Gray (±0.05%) appear on military-grade and calibration-grade parts. Resistors with no tolerance band are ±20%.

Temperature Coefficient Band (6-Band Only)

The 6th band indicates how much the resistance drifts per degree Celsius of temperature change, expressed in parts per million per Kelvin (ppm/K). A Brown 6th band means 100 ppm/K — the resistance shifts by 0.01% per °C. For a 10 kΩ 100 ppm/K resistor, a 25°C rise produces a 1 Ω shift. Low-ppm resistors (5–10 ppm/K, Violet or Blue) are used in precision voltage dividers, amplifier gain-setting networks, bridge circuits, and anywhere resistance stability matters more than absolute accuracy.

Resistor Color Code Reference Table — IEC 60062

The following table lists every color used in the IEC 60062 resistor color code system, its digit value, multiplier, tolerance, and temperature coefficient. Colors without an entry in a column cannot be used in that band position.

Color	Digit (D1–D3)	Multiplier	Tolerance	Temp. Coeff.
Black	0	×1 (×10⁰)		250 ppm/K
Brown	1	×10 (×10¹)	±1%	100 ppm/K
Red	2	×100 (×10²)	±2%	50 ppm/K
Orange	3	×1 kΩ (×10³)		15 ppm/K
Yellow	4	×10 kΩ (×10⁴)		25 ppm/K
Green	5	×100 kΩ (×10⁵)	±0.5%	20 ppm/K
Blue	6	×1 MΩ (×10⁶)	±0.25%	10 ppm/K
Violet	7	×10 MΩ (×10⁷)	±0.1%	5 ppm/K
Gray	8	×100 MΩ (×10⁸)	±0.05%	1 ppm/K
White	9	×1 GΩ (×10⁹)
Gold	—	×0.1	±5%
Silver	—	×0.01	±10%
None	—	—	±20%

How to Read a Resistor Color Code — Step by Step

Reading resistor bands is straightforward once you know the orientation and the color-to-digit mapping. The process is the same for 4-band, 5-band, and 6-band resistors, only the number of significant digits changes.

Orient the resistor. Turn the resistor so the tolerance band (Gold or Silver) is on the right. If unsure, the band with the largest physical gap between it and its neighbor is usually the tolerance band. On 5- and 6-band resistors the grouping of 3 digit bands on the left and 1–2 bands on the right is usually visible.
Read the digit bands from left to right. For a 4-band resistor, read D1 and D2. For 5- or 6-band, read D1, D2, and D3. Each color maps to a digit: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9.
Read the multiplier band. Multiply the digit number (e.g., 22 for Red-Red) by the multiplier. For Red-Red-Orange-Gold: 22 × 1,000 = 22,000 Ω = 22 kΩ.
Read the tolerance band. Gold = ±5%, Silver = ±10%, Brown = ±1%, Red = ±2%, and so on. This tells you the minimum and maximum allowable resistance.
For 6-band: read the temperature coefficient. The rightmost band on a 6-band resistor indicates ppm/K. Brown = 100 ppm/K is the most common.

Worked example — 4-band: Brown · Black · Orange · Gold

D1 = Brown = 1, D2 = Black = 0 → digits: 10
Multiplier = Orange = ×1,000
Resistance = 10 × 1,000 = 10,000 Ω = 10 kΩ
Tolerance = Gold = ±5% → range: 9,500–10,500 Ω

Worked example — 5-band: Red · Violet · Black · Brown · Brown

D1=2, D2=7, D3=0 → digits: 270
Multiplier = Brown = ×10
Resistance = 270 × 10 = 2,700 Ω = 2.7 kΩ
Tolerance = Brown = ±1% → range: 2,673–2,727 Ω

E-Series Preferred Values and How Resistor Tolerances Work

Resistors are manufactured in standardized preferred value series defined by IEC 60063, chosen so that adjacent values in the series overlap within their tolerance bands — guaranteeing that any arbitrary resistance target can be hit within tolerance by picking the nearest E-series value. The series are named after their number of values per decade.

E6 (±20%): 1.0, 1.5, 2.2, 3.3, 4.7, 6.8 (× any power of 10)

E12 (±10%): 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2

E24 (±5%): Adds 1.1, 1.3, 1.6, 2.0, 2.4, 3.0, 3.6, 4.3, 5.1, 6.2, 7.5, 9.1

E96 (±1%): 96 values per decade — much finer spacing, used in precision 5-band resistors

E192 (±0.5% and tighter): 192 values per decade for high-precision components

When a color → value decode produces a result like 9,100 Ω or 4,700 Ω, those are standard E24 values. If you get something like 9,732 Ω it is likely an E96 value. Non-standard results may indicate a misread, a non-standard component, or that you've read the bands in the wrong direction.

Temperature Coefficient (TCR) — 6-Band Precision Resistors

The temperature coefficient of resistance (TCR), measured in parts per million per Kelvin (ppm/K), describes how a resistor's value changes with temperature. A resistor with TCR = 100 ppm/K changes by 100 millionths of its value for each 1°C change in temperature. For a 10 kΩ resistor, that is 1 Ω per °C. Over a 50°C operating range, the total drift would be 50 Ω — a 0.5% shift on top of the manufacturing tolerance.

TCR matters most in circuits where absolute accuracy or ratio accuracy is critical: precision voltage references, Wheatstone bridge sensors, instrumentation amplifiers, analog-to-digital converter reference networks, and precision timers. Using two resistors with matched TCR in a ratio circuit (like a gain-setting pair) cancels the drift, which is why resistor networks (SIL or DIL packages) are popular — the components on a single substrate track each other very closely.

Typical TCR values by application:

General purpose (no 6th band): no spec, may be 200–500 ppm/K
Black band: 250 ppm/K — standard carbon film
Brown band: 100 ppm/K — general metal film
Red band: 50 ppm/K — precision metal film
Violet band: 5 ppm/K — ultra-precision wirewound or foil
Gray band: 1 ppm/K — bulk metal foil, used in calibration standards

How to Use This Resistor Color Code Calculator

Choose the band count. Select 4-Band, 5-Band, or 6-Band to match the resistor in your hand. The band selectors update immediately.
Color → Value mode. Select the color for each band using the dropdown. The color swatch next to each label updates live. The SVG diagram shows the resistor with your chosen colors. The Result panel displays the decoded resistance value, tolerance, and (for 6-band) temperature coefficient. Click the result to copy it.
Value → Color mode. Type a resistance value, choose the unit (Ω, kΩ, MΩ, GΩ), select the desired tolerance, and — for 6-band — a temperature coefficient. The calculator finds the matching band colors and shows them on the SVG diagram. Click 'Click to copy band names' to copy the full band description.
Switch between modes. The resistance value is automatically carried over when you switch tabs — decode a physical resistor in Color → Value, then switch to Value → Color to see alternative representations or verify your reading.
Your settings are saved. The calculator remembers your last band count, colors, and value across page reloads.

Frequently Asked Questions — Resistor Color Code

How do I tell which end of a resistor to start reading from?

The tolerance band (Gold, Silver) is always on the right. In practice, manufacturers often print it with a slightly wider gap from the adjacent band. If both ends look symmetrical, try reading in both directions — only one orientation produces a valid E-series standard value. Use this calculator to check both readings.

Why does my measured resistance differ from the color code?

A small deviation is expected and legal. The tolerance band defines the allowed spread — a 10 kΩ ±5% Gold resistor can measure 9,500–10,500 Ω. Additional factors: self-heating (resistance increases as the resistor dissipates power), temperature coefficient drift, probe contact resistance (typically 0.1–0.5 Ω), and component aging. For precision measurements, use 4-wire Kelvin sensing to eliminate probe resistance.

What are E-series values and why do they matter?

E-series (IEC 60063) are the standardized preferred resistance values: E12 (±10%), E24 (±5%), E48 (±2%), E96 (±1%), E192 (±0.5%). Adjacent values in a series are spaced so their tolerance bands overlap, guaranteeing any target resistance is achievable within tolerance. When you decode a resistor and get a non-standard number, you may have misread a band.

What does ppm/K mean on a 6-band resistor?

ppm/K (parts per million per Kelvin) is the temperature coefficient of resistance. 100 ppm/K means the resistance shifts by 0.01% for each 1°C change. For a 10 kΩ resistor: 10,000 × 0.0001 = 1 Ω per degree. Over a 25°C range, the drift is 25 Ω. Use low-ppm resistors (5–50 ppm/K) where temperature stability is critical.

Can I use this tool for SMD (surface-mount) resistors?

SMD resistors use a numeric code, not color bands. The 3-digit code (e.g., '472') encodes 2 significant digits + exponent: 47 × 10² = 4,700 Ω. The 4-digit code adds one digit: '4701' = 470 × 10¹ = 4,700 Ω. EIA-96 1% SMD resistors use a 2-digit + letter code requiring a separate lookup. Use the Value → Color mode here to confirm the target resistance value, then apply SMD coding separately.

What do Gold and Silver bands mean as multipliers vs. tolerance bands?

Gold and Silver serve double duty. As a multiplier band: Gold = ×0.1 and Silver = ×0.01, used for values below 10 Ω — for example, Yellow-Violet-Gold = 4.7 Ω (4-band). As a tolerance band (rightmost): Gold = ±5% and Silver = ±10%. Gold and Silver are never valid as significant digit bands.

Why is the first significant band never Black?

A Black first band would mean the leading digit is 0, producing a value like 04.7 kΩ = 4.7 kΩ — which would be written starting with Brown (B=4.7 kΩ directly). Manufacturers never use Black as the first band to avoid ambiguity, so if you see a Black first band you are either reading the resistor backwards or looking at a very unusual part.