How do I read resistor color bands?

For a 4-band resistor: Band 1 and 2 are digits, Band 3 is the multiplier, Band 4 is tolerance. For 5-band: Bands 1-3 are digits, Band 4 is multiplier, Band 5 is tolerance. Read from the side opposite the tolerance band (usually gold or silver).

What do the colors mean?

Digits: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9. Multipliers extend with Gold (×0.1) and Silver (×0.01) for resistors under 10 Ω. Tolerance: Brown (±1%), Red (±2%), Gold (±5%), Silver (±10%), None (±20%).

How do I know which side to read from?

The tolerance band is typically gold or silver in 4-band resistors — distinguishable from the other colors. Read from the opposite end. In 5-band resistors, look for a larger gap between the first four bands and the tolerance band. If both ends look similar, the correct direction gives a "standard" E12/E24 value.

What is the E-series of resistor values?

Standardized resistor values: E12 series (12 values per decade) for ±10% tolerance: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82. E24 for ±5% adds 12 more values. E96 for ±1% has 96 values per decade. All multiply by powers of 10.

How can I tell a 4-band from a 5-band resistor?

Simply count the bands. 4-band is the older standard; 5-band is more precise and common for 1% tolerance. The tolerance band is often a similar color in 5-band (typically brown), with a larger gap before it. Modern SMD resistors use printed digits instead of colors.

What if my resistor only has 3 bands?

It's a 4-band resistor with no tolerance band → ±20% (Carbon composition, vintage or very cheap). Value is read as if 4-band: D1, D2, multiplier, no tolerance. Modern hobby projects rarely use these — usually ±5% gold tolerance bands now standard.

How are SMD resistors marked?

SMD resistors use printed digit codes instead of colors. 3-digit: first 2 digits + power-of-10 multiplier (e.g., "103" = 10 × 10³ = 10 kΩ). 4-digit (precision): 3 digits + multiplier (e.g., "1002" = 100 × 10² = 10 kΩ). For under 10 Ω, "R" replaces decimal: "4R7" = 4.7 Ω.

Does the color code show power rating?

No. Power rating is determined by physical size, not bands. Typical sizes: 1/8 W (small), 1/4 W (medium), 1/2 W and 1 W (larger). For circuit design, calculate P = I²R and choose resistor large enough to dissipate that power with margin.

Resistor Color Code Calculator

Decode resistor color bands to find the resistance value and tolerance. Select 4 or 5 color bands to calculate the resistor value in ohms, kilohms, or megohms.

Through-hole resistors use colored bands instead of printed numbers to indicate their resistance value and tolerance. The color code is standardized worldwide (IEC 60062). Knowing how to read it lets electronics hobbyists, technicians, and engineers identify resistors at a glance — though with practice, it becomes almost instinctive.

The most common formats are 4-band (3 significant figures + multiplier + tolerance) and 5-band (3 digits + multiplier + tolerance). Newer or precision resistors may use 5-band; older or general-purpose may be 4-band. The colored bands are read from the side opposite the tolerance band, typically gold or silver (4-band) or brown/red (5-band precision).

The color-to-digit mapping is the same throughout: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9. Multiplier bands extend this with Gold (×0.1) and Silver (×0.01) for resistances below 10 Ω. Tolerance bands use Brown (±1%), Red (±2%), Gold (±5%), Silver (±10%), or none (±20%).

A common 1 kΩ resistor (1000 Ω) is brown-black-red-gold in 4-band: 1, 0, ×100, ±5%. In 5-band it's brown-black-black-brown-brown: 1, 0, 0, ×10, ±1%.

This calculator decodes any combination of color bands to give you the resistance value, tolerance, and the actual range of acceptable values. Useful for identifying unknown resistors, designing circuits, or just learning the color code.

Common applications: hobbyist electronics, circuit prototyping, repair work, education, kit assembly, and any work with through-hole resistors. SMD (surface-mount) resistors use different numerical codes covered separately.

Inputs

Number of Bands

Band 1 (1st digit)

Band 2 (2nd digit)

Band 3 (3rd digit, 5-band only)

Multiplier Band

Tolerance Band

Results

Resistance

1.00 kΩ

Tolerance

±5%

Range

950.00 Ω - 1.05 kΩ

Resistor Color Code Results

Parameter	Value
Resistance	1.00 kΩ
Resistance (exact)	1,000 Ω
Tolerance	±5%
Minimum Value	950.00 Ω
Maximum Value	1.05 kΩ
Band Count	4-band
Color Sequence	Brown, Black, Red
Base Value	10
Multiplier	×100

Last updated: May 29, 2026

Formula

**4-band resistor:** Value = (D1 × 10 + D2) × 10^Multiplier Tolerance = from 4th band. **5-band resistor (precision):** Value = (D1 × 100 + D2 × 10 + D3) × 10^Multiplier Tolerance = from 5th band. **Color code reference:** | Color | Digit | Multiplier | Tolerance | |---|---|---|---| | Black | 0 | ×1 | — | | Brown | 1 | ×10 | ±1% | | Red | 2 | ×100 | ±2% | | Orange | 3 | ×1k | — | | Yellow | 4 | ×10k | — | | Green | 5 | ×100k | ±0.5% | | Blue | 6 | ×1M | ±0.25% | | Violet | 7 | ×10M | ±0.1% | | Grey | 8 | — | ±0.05% | | White | 9 | — | — | | Gold | — | ×0.1 | ±5% | | Silver | — | ×0.01 | ±10% | | None | — | — | ±20% | **Worked example: 4-band brown-black-red-gold** D1 = brown = 1 D2 = black = 0 Multiplier = red = ×100 Tolerance = gold = ±5% Value: (1 × 10 + 0) × 100 = 1,000 Ω = 1 kΩ ±5% Range: 950-1050 Ω. **Worked example: 5-band yellow-violet-black-yellow-brown** D1 = yellow = 4 D2 = violet = 7 D3 = black = 0 Multiplier = yellow = ×10,000 Tolerance = brown = ±1% Value: (4 × 100 + 7 × 10 + 0) × 10,000 = 470 × 10,000 = 4,700,000 Ω = 4.7 MΩ ±1% Range: 4.653-4.747 MΩ. **Common resistor values (E12 series, ±10%):** 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82. (And × 10, × 100, × 1k, × 10k, × 100k, × 1M.) For example: 22 Ω, 220 Ω, 2.2 kΩ, 22 kΩ, 220 kΩ, 2.2 MΩ. **E series tolerance:** - **E6**: ±20% (rare today). - **E12**: ±10% (common). - **E24**: ±5% (most common). - **E48**: ±2%. - **E96**: ±1% (precision). - **E192**: ±0.5% (high precision). **Direction of reading:** The tolerance band is typically: - 4-band: gold (5%) or silver (10%) — distinguishable as the lone gold/silver band. - 5-band: usually a slight gap between the first 4 bands and the tolerance band. Read from the opposite side. If both ends look similar, hold the resistor either way; only one gives a "sensible" value. **SMD (surface-mount) resistor codes:** Different system — uses 3 or 4 digit codes printed on the resistor: - **3-digit**: first 2 digits + multiplier (e.g., "473" = 47 × 10³ = 47 kΩ). - **4-digit**: first 3 digits + multiplier (e.g., "4702" = 470 × 10² = 47 kΩ, precision). - **EIA-96 code**: 3-character system for tiny resistors. **Worked example: SMD code "104"** 10 × 10⁴ = 100,000 Ω = 100 kΩ. **Decade format with R:** For values under 10 Ω: R replaces decimal point. - "4R7" = 4.7 Ω. - "R47" = 0.47 Ω. - "47R" = 47 Ω. **Tolerance examples:** A 1 kΩ ±5% resistor: actual value 950-1050 Ω. A 1 kΩ ±1% resistor: actual value 990-1010 Ω. For tight applications (precision references, filters), use 1% or better. **Temperature coefficient (some resistors):** Color-coded sixth band on 6-band resistors: - Brown: 100 ppm/°C. - Red: 50 ppm/°C. - Orange: 15 ppm/°C. - Yellow: 25 ppm/°C. Standard carbon film: ~200-300 ppm/°C. Precision metal film: 25-50 ppm/°C. Wirewound: 10-20 ppm/°C. **Power rating (not in color code):** Determined by physical size, not bands. | Size | Typical wattage | |---|---| | Tiny (axial < 3mm) | 1/16 W | | Small (3-6mm) | 1/8 - 1/4 W | | Medium (6-10mm) | 1/2 W | | Large (10-20mm) | 1-5 W | | Wirewound (huge) | 10-50 W | **Common resistor types:** | Type | Tolerance | Use | |---|---|---| | Carbon film | ±5-10% | General hobby | | Metal film | ±1-2% | Precision | | Carbon composition | ±5-20% | Vintage | | Wirewound | ±1-5% | High power | | Foil | ±0.005% | Ultra-precision | | SMD thick film | ±1-5% | Modern SMD | | SMD thin film | ±0.1-0.5% | Precision SMD | **Reading tips:** - **Gold or silver band**: indicates tolerance side; bands read from opposite side. - **5-band reading**: tolerance band sometimes separated by larger gap. - **Both ends look similar**: try both directions; only one yields sensible value (E12/E24 standard). - **Faded colors**: use a multimeter to verify. - **Hard-to-distinguish red/orange/brown**: good lighting helps; in doubt, use multimeter.

How to use this calculator

Choose 4-band or 5-band resistor type.
Select each color band in order from the side opposite the tolerance band.
Tolerance band (gold/silver or precision color) goes last.
Calculator returns resistance value and tolerance range.
For unknown resistors, use a multimeter to verify.
Power rating is determined by physical size, not color bands.

Worked examples

4-band 1k resistor

**Scenario:** Brown-Black-Red-Gold. **Calculation:** D1 = 1 (brown), D2 = 0 (black), Multiplier = ×100 (red), Tolerance = ±5% (gold). Value: 10 × 100 = 1,000 Ω. **Result:** 1 kΩ ±5% — actual value 950-1050 Ω. One of the most common resistor values, used in countless circuits as base values for voltage dividers, current limiting, and signal conditioning.

5-band precision 4.7M

**Scenario:** Yellow-Violet-Black-Yellow-Brown. **Calculation:** D1 = 4 (yellow), D2 = 7 (violet), D3 = 0 (black), Multiplier = ×10,000 (yellow), Tolerance = ±1% (brown). Value: 470 × 10⁴ = 4.7 MΩ ±1%. **Result:** 4.7 MΩ ±1% — actual range 4.653-4.747 MΩ. Used in high-impedance circuits like multimeter input dividers, op-amp feedback, or timer circuits.

Decode physical resistor

**Scenario:** Hobbyist finds an unknown resistor with bands: orange-orange-brown-gold. **Calculation:** D1 = 3 (orange), D2 = 3 (orange), Multiplier = ×10 (brown), Tolerance = ±5% (gold). Value: 33 × 10 = 330 Ω. **Result:** 330 Ω ±5% — actual 313-347 Ω. Common LED current-limiting value. Use a multimeter to confirm if in doubt; precision components can verify the calculation.

When to use this calculator

**Use color code decoding for:**

- **Hobbyist electronics**: identifying parts in bins. - **Repair work**: finding values on circuit boards. - **Kit assembly**: verifying correct parts. - **Education**: learning electronic components. - **Inventory**: organizing resistor collections. - **Quality control**: visually verifying batches.

**When to use a multimeter instead:**

- **Faded colors**: heat or age can wash out bands. - **Burnt resistors**: changed value indicates damage. - **Mounted in circuit**: parallel paths can confuse readings; remove first. - **Critical applications**: always verify with measurement. - **Unfamiliar codes**: SMD or unusual schemes.

**Reading direction:**

Most 4-band resistors: - Gold/silver = tolerance band (last). - Read from opposite end.

If both ends look similar (e.g., 5-band with brown tolerance), look for: - Larger gap before tolerance band. - Sensible value in E12/E24 standard series.

**Standard E-series values:**

E12 (±10%): 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82. E24 (±5%): adds 11, 13, 16, 20, 24, 30, 36, 43, 51, 62, 75, 91.

These multiply by 10, 100, 1k, 10k, 100k, 1M. So if your decode gives 13 × 100 = 1300 Ω, that's a real E24 value.

If you decode something weird like 67 × 10 = 670 Ω — that's NOT a standard value. You probably read bands wrong; try reversing.

**Power dissipation considerations:**

The color code shows resistance and tolerance but NOT power rating. Physical size indicates power: - 1/8 W: 3.2 × 1.8 mm body. - 1/4 W: 6.5 × 2.5 mm. - 1/2 W: 9.5 × 3.5 mm. - 1 W: 11.5 × 5 mm.

For circuit design, calculate dissipation P = I²R and choose adequate size.

**Common applications:**

- **Hobbyist storage**: organize by value using color bands. - **Repair**: identify replacement part on broken board. - **Education**: teach electronics by reading codes. - **Kit verification**: ensure shipped parts match specifications. - **Old electronics restoration**: vintage devices use color codes.

**Sources of confusion:**

- **Brown vs red**: both reddish; brown has more orange undertone. - **Orange vs red**: orange is brighter; red is deeper. - **Grey vs silver**: grey has visible color; silver is metallic. - **Burnt resistors**: change value; visual code unreliable. - **Carbon composition resistors**: colors can fade with age.

**SMD codes (briefly):**

| Type | Format | Example | |---|---|---| | 3-digit | XYZ → XY × 10^Z | 103 = 10 kΩ | | 4-digit | WXYZ → WXY × 10^Z | 1002 = 10 kΩ | | EIA-96 | XYZ → table + letter | 01A = 100 Ω | | R notation | XRY → X.Y | 4R7 = 4.7 Ω |

**Software/tools:**

- **Color code apps**: iOS/Android scanners. - **Multimeter**: definitive measurement. - **Resistor sorting machines**: industrial. - **CAD libraries**: standard E-series values.

**Pitfalls:**

- **Reading backwards**: gives wrong value. - **Misidentifying tolerance band**: especially in 5-band. - **Confusing similar colors**: brown/red/orange in poor light. - **Assuming all 4-band**: some are 5- or 6-band. - **Ignoring physical condition**: cracked, burnt, or modified resistors. - **Mixing color codes**: SMD uses different system. - **Forgetting parallel resistance in-circuit**: remove for accurate reading.

Common mistakes to avoid

Reading the resistor from the wrong end (tolerance band first).
Confusing similar colors (brown vs red, orange vs red).
Misidentifying tolerance band as a digit (or vice versa).
Using 4-band rules on 5-band resistor (or vice versa).
Forgetting that physical size indicates power rating, not color.
Trusting visual reading without multimeter verification.
Mixing through-hole and SMD coding systems.
Ignoring that burnt/damaged resistors may have changed value.

Frequently Asked Questions

Sources & further reading

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