Pick the resistor band count, choose each color, then click calculate to decode the resistance value, tolerance range, and temperature coefficient (for 6-band resistors).
Tolerance: ±5%
Possible Range: 256.5 Ω to 283.5 Ω
What is a resistor color code calculator?
A resistor color code calculator converts colored bands on a resistor into a readable electrical value. Instead of guessing whether a resistor is 4.7 kΩ or 47 kΩ, you can decode it instantly and avoid wiring mistakes. This is especially useful in breadboarding, electronics repair, and exam preparation.
How resistor color codes work
Most through-hole resistors use 4, 5, or 6 color bands. Each band has a meaning based on its position:
- Significant digit bands: these define the base number.
- Multiplier band: this scales the base number up or down.
- Tolerance band: this gives allowed variation from nominal value.
- Temperature coefficient band (6-band): shows how value changes with temperature.
4-band resistor format
Band 1 and 2 are digits, band 3 is multiplier, and band 4 is tolerance. Example: Red, Violet, Brown, Gold = 27 × 10 = 270 Ω ±5%.
5-band resistor format
Bands 1-3 are digits, band 4 is multiplier, and band 5 is tolerance. This gives better precision than 4-band types. Example: Brown, Black, Black, Red, Brown = 100 × 100 = 10,000 Ω (10 kΩ) ±1%.
6-band resistor format
Like a 5-band resistor plus a sixth band for temperature coefficient (ppm/°C). This matters in high-stability or measurement circuits where temperature drift affects accuracy.
Common color meanings
These are the core digit values you'll use most often:
- Black = 0
- Brown = 1
- Red = 2
- Orange = 3
- Yellow = 4
- Green = 5
- Blue = 6
- Violet = 7
- Gray = 8
- White = 9
For tolerance, common values are: Brown ±1%, Red ±2%, Gold ±5%, Silver ±10%, and no band ±20%.
Step-by-step example
Suppose your resistor bands are Brown, Black, Red, Gold:
- Brown = 1
- Black = 0
- Base number = 10
- Red multiplier = ×100
- Nominal value = 10 × 100 = 1000 Ω (1 kΩ)
- Gold tolerance = ±5%
So the resistor can be anywhere from 950 Ω to 1050 Ω.
Common mistakes and how to avoid them
- Reading from the wrong side: tolerance band is usually spaced farther from others; read from the opposite side.
- Confusing red and brown: use bright lighting or a magnifier for old parts.
- Ignoring tolerance: two resistors with same nominal value may behave differently in precise circuits.
- Not checking with a meter: if in doubt, confirm with a multimeter.
Why this calculator helps
Manual decoding is good to learn, but a calculator is faster and reduces mistakes. It also gives immediate min/max range from tolerance, which is useful when checking if a measured value is still within spec.
Final thoughts
Whether you are a beginner learning electronics or a technician troubleshooting boards, the resistor color code calculator saves time and improves reliability. Use it with your multimeter and schematic for the best results.