Resistor Calculator
Decode resistor colour bands and compute series and parallel networks.
About Resistor Calculator
Resistor colour codes follow IEC 60062. Each colour band encodes a digit (0–9), a multiplier power of ten, a tolerance percentage, and (for 6-band precision resistors) a temperature coefficient. Reading the bands from the end closest to the lead, the first 2 (or 3) bands form the mantissa, the next band gives the multiplier, the tolerance band defines the accuracy class, and the optional 6th band specifies temperature stability in ppm/°C.
Formulas
4-band value
R = (10 × band1 + band2) × multiplier
5/6-band value
R = (100 × band1 + 10 × band2 + band3) × multiplier
Series
Series R = R1 + R2 + ... + Rn
Parallel
1/Rparallel = 1/R1 + 1/R2 + ...
Worked example
With the default values below, Resistor Calculator returns Resistance of 1,000.0000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Modeone of Colour Code Decoder, Series Network, Parallel Network
- Colour Code Decoder
- Number of Bandsone of 4 bands (±5% / ±10%), 5 bands (±1% / ±2%), 6 bands (±1% + temp coeff)
- 4 bands (±5% / ±10%)
- Band 1 (1st digit)one of Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White
- Brown
- Band 2 (2nd digit)one of Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White
- Black
- Band 3 (3rd digit)one of Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White
- Black
- Multiplier Bandone of Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gold, Silver
- Red
- Tolerance Bandone of Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, Gold, Silver, None (±20%)
- Gold
- Temperature Coefficient Band (6-band only)one of Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey
- Brown
- R1minimum 0 Ω
- 100 Ω
- R2minimum 0 Ω
- 200 Ω
- R3 (optional, 0 to omit)minimum 0 Ω
- 0 Ω
- R4 (optional, 0 to omit)minimum 0 Ω
- 0 Ω
Results
- Resistance
- 1,000.0000 Ω
- Tolerance
- ±5%
- Value Range
- 1.000 kΩ – 1.000 kΩ
- Temperature Coefficient
- n/a
- Band Sequence
- brown black | red | gold
Step by step
- 1Digit bands= brown(1) black(0) = 10
- 2Multiplier= red → × 100
- 3Resistance= 1.000 kΩ
- 4Tolerance= ±5% → 1.000 kΩ to 1.000 kΩ
Assumptions and limits
- The result is derived only from the 12 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How do I tell which end of a resistor to read from?
Start from the band closest to a lead. The tolerance band (gold or silver for 4-band) is always at the opposite end. If in doubt, read both ways and look up both values — only one will be a standard E-series value.
Why do parallel resistors always give a smaller total?
Adding parallel paths gives current more ways to flow, reducing the total opposition. The result is always less than the smallest individual resistor.
What does 6-band mean?
6-band resistors add a temperature coefficient band, specifying how much the resistance drifts per degree Celsius. Used in precision circuits where thermal stability matters.
What are standard E-series resistor values?
The E12, E24, E48, E96 and E192 series define preferred values based on logarithmic spacing. For example, E12 values are: 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2 (and their decade multiples).