Resistor Color Code Calculator
Ohms, tolerance, and range from 4 band color codes.
What it does
Resistors print values as color bands because tiny bodies defeat text: two digit bands, a multiplier, and a tolerance. Yellow violet red gold decodes to 47 times 100 at five percent, the famous 4.7 kΩ workhorse.
The tool above reads any four band code. Pick each color for resistance with tolerance and the actual min max range.
Direction reads from the tolerance end. Gold and silver live only as multiplier or tolerance, so the metallic band sits right while plain color bands start left.
Five band resistors add a third digit for precision parts. This page covers four band codes that dominate general electronics drawers.
How to use
- Hold the resistor with gold or silver band right.
- Pick the first two band colors left to right.
- Pick the multiplier band third.
- Read tolerance fourth and check the range.
Formula
- digits
- Black 0 through white 9 in order.
- multiplier
- Power of ten, or 0.1 gold and 0.01 silver.
- tolerance
- Percent spread: gold 5, silver 10, brown 1.
Kilo and mega prefixes group thousands: 4700 Ω prints as 4.7 kΩ, matching how schematics label parts.
Worked example
Example: yellow violet red gold
Bands yellow, violet, red, gold.
- Digits: yellow 4 and violet 7 make 47.
- Multiplier: red means x100. Value 4700 Ω.
- Display: 4.7 kΩ.
- Tolerance: gold ±5%. Range 4465 to 4935 Ω, shown as 4.46 to 4.93 kΩ.
Reference table
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | x1 | - |
| Brown | 1 | x10 | ±1% |
| Red | 2 | x100 | ±2% |
| Orange | 3 | x1k | - |
| Yellow | 4 | x10k | - |
| Green | 5 | x100k | ±0.5% |
| Blue | 6 | x1M | ±0.25% |
| Violet | 7 | x10M | ±0.1% |
| Gold | - | x0.1 | ±5% |
| Silver | - | x0.01 | ±10% |
Limits
- Four band codes only. Five band precision differs.
- Heat drift moves real values with temperature.
- Faded colors misread. Meters arbitrate doubt.
- Wattage ratings need separate sizing.
Common mistakes
- Reading backwards from the wrong end.
- Confusing red multiplier with red tolerance.
- Assuming exact value instead of the range.
- Ignoring wattage while nailing ohms.
- Trusting sun bleached bands.
Try it yourself
Quick checks. Answers sit tucked under each question.
Brown black red gold?
10 x 100 = 1000 Ω, so 1 kΩ ±5%.
Red red brown gold?
22 x 10 = 220 Ω ±5%.
Questions
How do I read resistor colors?
Two digits, multiplier, tolerance. Yellow violet red gold is 4.7 kΩ ±5%.
Which end do I start from?
Opposite gold or silver. The metallic band marks tolerance at the right.
What is a 5 band resistor?
Three digits plus multiplier for 1% precision parts.
Why kΩ and MΩ?
Shorthand for thousands and millions of ohms on schematics.
Does tolerance matter?
For dividers and timing, yes. For LED dropping, barely.
Can colors fade?
Yes with heat and sun. Confirm odd readings with a meter.