Understanding the resistor colour code is essential for identifying the exact resistance value used in electronic circuits. Each colour band represents digits, multipliers, tolerance, and sometimes temperature coefficient. By learning how to read 3-band, 4-band, 5-band, and 6-band resistor colour codes, anyone can easily calculate the resistor value without confusion.
Universal Resistor Colour Code Calculator
(3, 4, 5, 6 Band)
How To Use the Universal Resistor Colour Code Calculator
This tool calculates the resistance value from resistor colour bands. Choose the resistor type (3-band, 4-band, 5-band or 6-band) from the top dropdown. Then select the colour for each band shown. Click CALCULATE and the calculator will show the resistance in ohms (Ω), kilohms (kΩ) or megohms (MΩ), plus tolerance and TCR (for 6-band resistors).
SELECT BAND TYPE
• 3-band — two digit bands + multiplier (used for very simple resistors).
• 4-band — two digit bands + multiplier + tolerance (very common).
• 5-band — three digit bands + multiplier + tolerance (used for precision resistors).
• 6-band — three digit bands + multiplier + tolerance + TCR ( temperature coefficient, used for high precision / temperature-sensitive resistors).
WHAT EACH SELECT FIELD MEANS:
• 1st Band (1st digit) — the first significant digit of the resistor value. Example: Brown = 1, Red = 2, Orange = 3, etc.
• 2nd Band (2nd digit) — the second significant digit. For 5- and 6-band resistors, there is also a 3rd Band (3rd digit).
• 3rd Band (only for 5- or 6-band) — the third significant digit (used for more precise values).
• Multiplier — multiplies the combined digits by a power of ten or a fraction. Example: ×1, ×10, ×100, ×1k (×1000), ×0.1 (gold), ×0.01 (silver). This determines the order of magnitude.
• Tolerance — the percentage the actual resistance may vary from the nominal value (for example ±1%, ±5%).
• TCR (Temperature Coefficient of Resistance, only in 6-band) — how much the resistor value changes with temperature, expressed in parts per million per Kelvin (ppm/K). Lower TCR = more stable with temperature.
• 2nd Band (2nd digit) — the second significant digit. For 5- and 6-band resistors, there is also a 3rd Band (3rd digit).
• 3rd Band (only for 5- or 6-band) — the third significant digit (used for more precise values).
• Multiplier — multiplies the combined digits by a power of ten or a fraction. Example: ×1, ×10, ×100, ×1k (×1000), ×0.1 (gold), ×0.01 (silver). This determines the order of magnitude.
• Tolerance — the percentage the actual resistance may vary from the nominal value (for example ±1%, ±5%).
• TCR (Temperature Coefficient of Resistance, only in 6-band) — how much the resistor value changes with temperature, expressed in parts per million per Kelvin (ppm/K). Lower TCR = more stable with temperature.
STEP-BY-STEP EXAMPLES (follow these inside the page):
Example A — 3-Band resistor (Black, Brown, Red multiplier):
• Step 1: Choose “3-Band”.
• Step 2: 1st Band = Black (0), 2nd Band = Brown (1). That gives the digits “0” and “1” => together = 01 → numeric value 1 (leading zeros drop naturally).
• Step 3: Multiplier = Red (×100). Calculation: 1 × 100 = 100 Ω.
• Result: 100 Ω.
Example B — 4-Band resistor (Brown, Black, Red, Gold):
• Step 1: Choose “4-Band”.
• Step 2: 1st Band = Brown (1), 2nd Band = Black (0) → digits = 10.
• Step 3: Multiplier = Red (×100) → 10 × 100 = 1000 Ω = 1 kΩ.
• Step 4: Tolerance = Gold (±5%). That means the actual resistor could be between 950 Ω and 1050 Ω. (How: 1 kΩ ±5% → 1000 ± 50 Ω.)
Example C — 5-Band resistor (Green, Blue, Brown, Orange multiplier, Brown tolerance):
• Step 1: Choose “5-Band”.
• Step 2:
1st = Green (5),
2nd = Blue (6),
3rd = Brown (1) → digits = 561.
• Step 3: Multiplier = Orange (×1k) → 561 × 1,000 = 561,000 Ω = 561 kΩ.
• Step 4: Tolerance = Brown (±1%) → actual range = 561 kΩ ± 1% → 555.39 kΩ to 566.61 kΩ.
Example D — 6-Band resistor (Orange, Orange, Black, Brown multiplier, Red tolerance, Brown TCR):
• Step 1: Choose “6-Band”.
• Step 2: 1st = Orange (3), 2nd = Orange (3), 3rd = Black (0) → digits = 330.
• Step 3: Multiplier = Brown (×10) → 330 × 10 = 3,300 Ω = 3.3 kΩ.
• Step 4: Tolerance = Red (±2%) → range = 3.3 kΩ ±2% → 3.234 kΩ to 3.366 kΩ.
• Step 5: TCR = Brown (100 ppm/K) — this tells how much the resistance changes per degree change in temperature. For example, 100 ppm/K on 3.3 kΩ is 3.3 kΩ × 100 × 10⁻⁶ = 0.33 Ω change per Kelvin.
HOW THE CALCULATOR DISPLAYS THE RESULT:
• Resistance is shown in the best unit (Ω, kΩ, MΩ).
• Tolerance is shown as a percentage. You can calculate the minimum and maximum possible values by applying the tolerance percentage to the nominal resistance.
• If TCR is present (6-band), it will show the TCR code or value so advanced users can adjust for temperature effects.
UNDERSTANDING COMMON COLORS QUICK REFERENCE:
• Digit colors: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9.
• Multiplier special: Gold = ×0.1, Silver = ×0.01 (used rarely for very small resistances).
• Tolerance common: Brown ±1%, Red ±2%, Gold ±5%, Silver ±10%. (There are other tolerance colours — use what the dropdown shows.)
• TCR common: Brown, Red, Orange, etc. (lowest TCR values are for precision resistors).
SIMPLE CHECKS & TROUBLESHOOTING:
• If the result shows a very small number with a decimal, that is OK (some resistors are <1 Ω if the multiplier is 0.1 or 0.01).
• If digits start with 0 (e.g., first band is black), the calculator still uses them properly (01 + multiplier yields the correct value).
• For 5- and 6-band resistors, be sure to use the 3rd digit field — missing that makes the value wrong.
• If you don’t know which band is which physically on the resistor, remember bands are read from one end: the tolerance band is usually separated a little or is gold/silver; read left to right with the tolerance band on the right.
HOW TO MANUALLY CALCULATE TOLERANCE RANGE:
• Example: Nominal = 10 kΩ, Tolerance = ±5% → Minimum = 10,000 − (10,000 × 0.05) = 9,500 Ω, Maximum = 10,000 + (10,000 × 0.05) = 10,500 Ω.
EXTRA NOTES FOR USERS:
• 4-band is common for standard components; 5-band is used for higher precision (more significant digits).
• 6-band adds TCR for temperature-sensitive applications.
• Use the multiplier carefully when you see gold/silver — they reduce the base number (rare but valid).
• If unsure: take a photo of the resistor, zoom in to identify the band closest to one end (the tolerance band is usually separated or a different colour), then use the calculator.