Resistor Color Code Calculator
Decode 4-band, 5-band and 6-band resistor color codes — value, tolerance, temperature coefficient, minimum and maximum.
Resistance
4.7 kΩ
4,700 Ω
Minimum
4.47 kΩ
Tolerance 5%
Maximum
4.94 kΩ
Tolerance 5%
Colour codes follow the IEC 60062 standard: 4-band resistors carry two digits, a multiplier and a tolerance; 5-band adds a third digit; 6-band adds the temperature coefficient.
Last updated: June 2026
How this calculator is verified
Checked by True Calculator automated test suite on
- Formula verified against a published worked example in the automated test suite
- Edge cases (zero, negative, boundary and unit-mismatch inputs) covered by unit tests
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
Use this calculator whenever you are sorting a component box, repairing a device, or building a circuit from a schematic that only lists resistance values. Hobby electronics in India often relies on through-hole resistors bought in assorted packs where the bands are the only label. Before soldering a divider network, an LED current limiter or an op-amp gain resistor, decode the bands and check that the value and tolerance fit the design. It also helps when a supplier lists resistors by colour code rather than printed value, or when faded print makes the number unreadable. Pair the result with a quick multimeter check to confirm what the bands claim.
How to Use This Calculator
- Step 1: Hold the resistor with the tolerance band (gold or silver) on the right.
- Step 2: Enter the colour of the first band as the first digit (0–9).
- Step 3: Enter the second band's colour as the second digit, then the multiplier band.
- Step 4: Pick the tolerance band colour and read the value, minimum and maximum resistance.
Worked Example
A resistor shows yellow, violet, red and gold bands from left to right. Enter digit 4 for yellow, digit 7 for violet, multiplier 2 for red and 5% tolerance for gold. The calculator returns 4700 Ω: (4 × 10 + 7) × 10². With ±5% tolerance, the acceptable range runs from 4465 Ω to 4935 Ω. You can now verify the resistor with a multimeter and confirm it is within the marked spec.
Tips and Common Mistakes
- •Tip 1: Memorise the mnemonic 'BB ROY of Great Britain' — black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9.
- •Tip 2: When the multiplier band looks worn, measure the resistor instead of guessing the colour.
- •Tip 3: For 5-band resistors the third band is another digit — read the value as three digits times the multiplier.
- ✗Mistake 1: Avoid reading the bands in the wrong direction — the tolerance band always sits at the right end.
- ✗Mistake 2: Don't use the nominal value alone in precision circuits; always work with the tolerance range.
Frequently Asked Questions
How do I read a 4-band resistor?
The first two bands are the significant digits, the third band is the multiplier (a power of ten) and the fourth band is the tolerance. For example, yellow (4), violet (7) and red (×100) gives 4700 Ω, which with a gold band is ±5%.
Why do resistors have a tolerance?
Manufacturing cannot hit an exact value, so each resistor is guaranteed to fall within a percentage of the stated value. A 4700 Ω resistor with 5% tolerance measures anywhere between 4465 Ω and 4935 Ω and is still in spec.
What do the tolerance band colours mean?
Brown means ±1%, red ±2%, gold ±5% and silver ±10%. In hobby electronics, gold and silver bands are the most common on standard through-hole resistors.
Which multiplier band should I pick for a 1 MΩ resistor?
For 1 MΩ you read brown (1), black (0) and a green multiplier band (×100,000), giving 10 × 100,000 = 1,000,000 Ω. The multiplier band counts up from ×1 at black to ×1,000,000,000 at white.
How do I identify a resistor when I only see its value?
Work backwards: write the value in engineering notation with one digit before the decimal, then convert the decimal part to the multiplier band. 4700 Ω becomes 4.7 kΩ, which is digits 4 and 7 with a red multiplier.
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