Calculator
Example Data Table
| Input | Meaning | Nominal Value | Common Use |
|---|---|---|---|
| Brown, Black, Orange, Gold | 10 × 1,000 pF ±5% | 10 nF | Signal coupling |
| Yellow, Violet, Orange, Silver | 47 × 1,000 pF ±10% | 47 nF | Filter network |
| Printed code 104 | 10 × 10,000 pF | 100 nF | Bypass capacitor |
| Printed code 2R2 | 2.2 pF | 2.2 pF | RF tuning |
Formula Used
Color value: capacitance in pF = significant digits × multiplier.
Printed code: capacitance in pF = first two digits × 10third digit.
Tolerance range: minimum = nominal × (1 - tolerance ÷ 100). Maximum = nominal × (1 + tolerance ÷ 100).
Capacitive reactance: Xc = 1 ÷ (2πfC), where f is frequency in hertz and C is capacitance in farads.
Parallel bank: Ctotal = C × quantity. Series bank: Ctotal = C ÷ quantity for equal capacitors.
Energy: E = 0.5 × C × V². RC time: τ = R × C.
How To Use This Calculator
Select whether you are reading color bands or a printed marking code. Choose each capacitor color in order. Use three significant digits only when the part has that style. Add tolerance, voltage, frequency, resistance, and quantity when needed. Press calculate. The result appears above the form. Use CSV or PDF download for records.
Article
Understanding Capacitor Color Codes
Capacitor color bands help identify capacitance without printed numbers. Older mica, ceramic, and molded capacitors often use this method. The first colors show significant digits. The multiplier color scales the number in picofarads. The tolerance color shows the allowed manufacturing range. A voltage color may also appear on some parts.
Why This Calculator Helps
This calculator reduces reading errors and unit mistakes. It converts picofarads, nanofarads, microfarads, and farads in one step. It also estimates the tolerance limits, capacitive reactance, stored energy, and bank value. These extra results help during repair, inspection, prototyping, and parts replacement.
Reading The Bands
Start from the end nearest the first band. Choose the first digit color. Choose the second digit color. Use the third significant digit when your part uses a five band style. Then select the multiplier. Finally select tolerance and voltage, when those bands exist. If a printed code is present, such as 104, use the marking option.
Electrical Meaning
Capacitance tells how much charge a part can store for each volt. Higher capacitance gives lower reactance at the same frequency. This matters in filters, coupling networks, timing circuits, and power supply bypass paths. Tolerance shows the possible spread around the nominal value. A ten percent part can be slightly above or below its marked value.
Design Notes
Always compare the voltage result with the actual circuit voltage. Use a safety margin. Old color code standards can vary by manufacturer. Confirm critical parts with a meter or datasheet. For high voltage, pulse, safety, or mains circuits, use the correct certified part. Do not replace safety capacitors with ordinary capacitors.
Practical Workflow
Enter the color bands first. Review the converted value. Check the minimum and maximum tolerance range. Add frequency when you need reactance. Add quantity when building a capacitor bank. Select series or parallel wiring. Export the result when you need a record for a repair sheet, bill of materials, or classroom example.
Common Mistakes
Many errors come from reversed bands, faded paint, or mixing resistor and capacitor charts. Clean the part gently before reading. Compare nearby circuit parts when possible. Photograph the bands before removal. This gives a backup reference if labels become damaged during repair work.
FAQs
1. What does a capacitor color code show?
It shows the nominal capacitance, multiplier, tolerance, and sometimes voltage rating. The final value is usually read in picofarads before conversion to nF, µF, or F.
2. What does the third digit mean in 104?
In a three digit marking, the first two digits are significant. The third digit is the power of ten multiplier. Code 104 means 10 × 10,000 pF, or 100 nF.
3. Is the voltage color always reliable?
No. Voltage color rules can vary with older parts and manufacturers. Use the result as a guide. Confirm critical or high voltage components with a datasheet or direct part marking.
4. Why does the calculator show tolerance range?
Real capacitors are not always exactly equal to their marked value. Tolerance range shows the expected minimum and maximum value based on the selected tolerance band.
5. How is capacitive reactance useful?
Capacitive reactance shows opposition to AC at a selected frequency. It helps estimate capacitor behavior in filters, coupling stages, timing paths, and noise bypass circuits.
6. Can I calculate series capacitor banks?
Yes. Select series and enter the quantity. For equal capacitors, total capacitance is one capacitor value divided by the number of capacitors.
7. Can I use this for ceramic capacitor codes?
Yes. Use the printed code option for markings such as 101, 472, 103, and 104. The calculator treats the result as picofarads before converting it.
8. Should I replace a capacitor only by capacitance?
No. Match capacitance, voltage rating, tolerance, dielectric type, temperature class, and safety rating. This is especially important for mains and pulse circuits.