Capacitor Code Calculator
Decode ceramic capacitor markings (103, 104, 474) to actual values. Convert between pF, nF, and µF units instantly.
Calculator
Tolerance Letter Codes
How to Use This Calculator
This calculator helps you decode the cryptic numbers printed on ceramic capacitors and convert between different capacitance units.
- Decode Mode — Enter a code like "104" to find the actual capacitance
- Find Code Mode — Enter a value to find what code would be printed
- Quick Values — Click common values for instant conversion
The calculator also shows tolerance codes (J, K, M) and can identify voltage ratings when present in extended codes.
Understanding the Code System
Ceramic capacitors use a 3-digit code system where the value is expressed in picofarads (pF):
The 3-Digit Code
Multiplier Values
| 3rd Digit | Multiplier | Example | Result |
|---|---|---|---|
| 0 | ×1 | 100 | 10 pF |
| 1 | ×10 | 101 | 100 pF |
| 2 | ×100 | 102 | 1,000 pF = 1 nF |
| 3 | ×1,000 | 103 | 10,000 pF = 10 nF |
| 4 | ×10,000 | 104 | 100,000 pF = 100 nF |
| 5 | ×100,000 | 105 | 1,000,000 pF = 1 µF |
Tolerance Letters
A letter after the numeric code indicates tolerance:
- J = ±5% (most common for ceramic)
- K = ±10%
- M = ±20%
- F = ±1% (precision)
- G = ±2%
Common Examples
| Code | pF | nF | µF | Common Use |
|---|---|---|---|---|
| 100 | 10 | 0.01 | 0.00001 | RF circuits, crystal loading |
| 101 | 100 | 0.1 | 0.0001 | High-frequency bypass |
| 102 | 1,000 | 1 | 0.001 | RF decoupling |
| 103 | 10,000 | 10 | 0.01 | Audio coupling |
| 104 | 100,000 | 100 | 0.1 | IC decoupling (very common) |
| 105 | 1,000,000 | 1,000 | 1 | Bulk decoupling |
| 224 | 220,000 | 220 | 0.22 | Power supply filtering |
| 474 | 470,000 | 470 | 0.47 | Motor run, filtering |
Capacitor Types and Markings
Ceramic Capacitors (MLCC)
Use the 3-digit code system. Small SMD sizes may have no marking at all. Common dielectrics: C0G/NP0 (stable), X7R, X5R, Y5V (high capacitance but less stable).
Film Capacitors
Often use the same 3-digit code, but larger ones may print the actual value (e.g., "0.1µF" or "100nF").
Electrolytic Capacitors
Usually print the actual value and voltage directly (e.g., "100µF 25V"). No code conversion needed.
Tantalum Capacitors
SMD tantalums use a code that includes value and voltage. The case size often indicates voltage rating (e.g., A=10V, B=16V, C=25V, D=35V).
Frequently Asked Questions
Why do capacitors use this confusing code?
The 3-digit code fits on tiny components where printing "100,000 pF" is impossible. It's actually quite logical once you understand that the third digit is a multiplier.
What if I see only 2 digits?
Two-digit codes (like "10" or "47") represent the value directly in picofarads. So "10" = 10 pF and "47" = 47 pF. This is used for very small capacitors.
What does "104K" mean?
The "104" means 100,000 pF (100 nF), and the "K" indicates ±10% tolerance. So it's a 100nF capacitor with 10% tolerance.
How do I know the voltage rating?
Voltage is sometimes printed separately (e.g., "50V") or indicated by a letter code. When in doubt, check the datasheet or assume 50V for unmarked ceramics. Never exceed the voltage rating.
What's the difference between 100nF and 0.1µF?
They're exactly the same value, just different units. 1 µF = 1000 nF = 1,000,000 pF. Europeans tend to use nF more often, while Americans often use µF.
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