| Color | Digit | Multiplier | Tolerance | Temp Coef. |
|---|---|---|---|---|
| Black | 0 | ×1 (1Ω) | — | 250 ppm/K |
| Brown | 1 | ×10 (10Ω) | ±1% | 100 ppm/K |
| Red | 2 | ×100 (100Ω) | ±2% | 50 ppm/K |
| Orange | 3 | ×1k (1kΩ) | — | 15 ppm/K |
| Yellow | 4 | ×10k (10kΩ) | — | 25 ppm/K |
| Green | 5 | ×100k (100kΩ) | ±0.5% | 20 ppm/K |
| Blue | 6 | ×1M (1MΩ) | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10M (10MΩ) | ±0.1% | 5 ppm/K |
| Gray | 8 | ×100M (100MΩ) | ±0.05% | 1 ppm/K |
| White | 9 | ×1G (1GΩ) | — | — |
| Gold | — | ×0.1 (÷10) | ±5% | — |
| Silver | — | ×0.01 (÷100) | ±10% | — |
How to Read Resistor Color Codes
Resistors use colored bands to indicate their resistance value, tolerance, and sometimes temperature coefficient. Learning to read these codes is an essential skill for anyone working with electronics. This calculator supports 4-band, 5-band, and 6-band resistors.
🧠 Color Code Mnemonic
Here's a popular way to remember the color sequence (0-9):
"Big Brown Rabbits Often Yield Great Big Vocal Groans When Gingerly Slapped"
Black (0), Brown (1), Red (2), Orange (3), Yellow (4), Green (5), Blue (6), Violet (7), Gray (8), White (9)
Note: Gold and Silver are special — they appear only as multipliers or tolerance bands.
4-Band Resistors
The most common type. The first two bands indicate the significant digits, the third band is the multiplier, and the fourth band shows tolerance. For example: Brown-Black-Red-Gold = 10 × 100 = 1,000Ω (1kΩ) with ±5% tolerance.
5-Band Resistors
Used for precision resistors. Three significant digit bands, one multiplier band, and one tolerance band. These allow for more precise values like 4.7kΩ (Yellow-Violet-Black-Brown-Brown = 470 × 10 = 4,700Ω ±1%).
6-Band Resistors
Include all the bands of a 5-band resistor plus a sixth band for temperature coefficient. This indicates how much the resistance changes with temperature, measured in ppm/K (parts per million per Kelvin).
Which End to Start From?
This can be tricky! Here are some tips:
- The tolerance band (gold, silver, or a wider gap) is usually on the right side
- The first band is typically closer to one end of the resistor
- Gold and silver can only be multipliers or tolerance — never the first digit band
- If in doubt, measure with a multimeter to verify
Common Resistor Values (E12 Series)
Standard resistors come in preferred values. The E12 series (±10% tolerance) includes: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82 — and these values multiplied by powers of 10. For example: 10Ω, 100Ω, 1kΩ, 10kΩ, 100kΩ, 1MΩ are all standard values.
💡 SMD Resistors
Surface-mount resistors use numeric codes instead of colors. "103" means 10 × 10³ = 10kΩ. The last digit is always the multiplier (number of zeros to add).
⚠️ Power Rating
Color bands don't indicate power rating — that's determined by physical size. Common sizes: 1/8W, 1/4W, 1/2W, 1W, 2W. Exceeding power rating will cause the resistor to overheat.
🔍 When in Doubt
If colors are hard to distinguish (especially brown/red/orange), use a multimeter. Measure resistance directly and you'll know for sure.
🌡️ Temperature Effects
The temperature coefficient matters for precision circuits. A 100 ppm/K resistor changes by 0.01% per degree Celsius. For most hobby projects, this is negligible.
Frequently Asked Questions
What does the tolerance mean?
Tolerance indicates how much the actual resistance can vary from the marked value. A 1kΩ resistor with ±5% tolerance can have an actual value between 950Ω and 1050Ω. Precision circuits need tighter tolerances (±1% or better).
Why are there different band counts?
4-band resistors (±5-20% tolerance) are cheapest and sufficient for most applications. 5-band resistors provide more precision with an extra digit. 6-band add temperature stability information for critical applications like instrumentation.
Can I use a higher tolerance resistor than needed?
Yes! A ±1% resistor works fine where ±5% is specified. You're paying for precision you might not need, but it won't cause problems. Going the other way (lower precision than required) can cause circuit issues.
What's a "zero-ohm" resistor?
A resistor with a single black band is a 0Ω "jumper" — essentially a wire in resistor form. They're used in PCBs to cross traces without using a separate wire jumper.
Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are computed using standard formulas and should be verified for critical applications.
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Resistor Color Code Calculator FAQ
What is Resistor Color Code Calculator?
Resistor Color Code Calculator is a free engineering & physics tool that helps you Decode 4, 5, and 6 band resistor color codes to find resistance values.
How do I use Resistor Color Code Calculator?
Enter your input values, review the calculated output, and adjust inputs until you reach the result you need. The result updates in your browser.
Is Resistor Color Code Calculator private?
Yes. Calculations run locally in your browser. Inputs are not uploaded to a server by default, and refreshing the page clears session data.
Does Resistor Color Code Calculator require an account or installation?
No. You can use this tool directly in your browser without sign-up or software installation.
How accurate are results from Resistor Color Code Calculator?
This tool applies standard formulas or deterministic processing logic for estimates. For medical, legal, tax, or investment decisions, verify with a qualified professional.
Can I save or share outputs from Resistor Color Code Calculator?
You can bookmark this page and copy outputs manually. Results are not persisted in your account and are typically not embedded in the URL.