Ceramic Capacitor Voltage Derating
C_eff = C_rated × factor
Quick answer
This calculator solves C_eff = C_rated × derating_factor for Effective Capacitance. With Rated Capacitance 0.22 mF, Derating Factor 50 %, the result is 110 µF. It solves in 3 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
Class II and Class III ceramic capacitors (X7R, X5R, Y5V, Z5U) lose significant capacitance when a DC bias voltage is applied. A 10 µF X5R capacitor rated at 10 V may lose 50-80% of its capacitance when biased at 8 V. The derating factor represents the fraction of rated capacitance available at the operating DC bias. This effect is a fundamental material property of high-permittivity ceramics (barium titanate) and cannot be designed out. Class I ceramics (C0G/NP0) do not exhibit this effect but are limited to small capacitance values.
Variables
- C_eff — Effective capacitance at operating voltage (F)
- C_rated — Rated (zero-bias) capacitance (F)
- factor — Derating factor (0 to 1)
Practical Notes
Always check the manufacturer DC bias curves when selecting MLCC capacitors. A common rule of thumb is to derate by 50% for X5R/X7R at half the rated voltage, but actual derating varies significantly between manufacturers and packages. Larger case sizes generally have better voltage derating characteristics. Consider using multiple smaller-value capacitors in parallel to mitigate derating effects.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| Ceff | Effective Capacitance | µF | pF, nF, µF, mF, F |
| Crated | Rated Capacitance | µF | pF, nF, µF, mF, F |
| factor | Derating Factor | — | —, % |
Step by step
- 1. What you know: Rated Capacitance 0.22 mF, Derating Factor 50 %
- 2. The relation: C_eff = C_rated × derating_factor
- 3. Substitute: Crated = 0.22 mF, factor = 50 %
- 4. Result: Effective Capacitance = 110 µF
Nearest standard component values
| Series | Nearest value | Error |
|---|---|---|
| E12 | 100 µF | 9.1% |
| E24 | 110 µF | 1.2e-14% |
Worked examples
Minimum range
Given: Rated Capacitance 0.22 µF, Derating Factor 2.5 %
Result: Effective Capacitance = 5.5 nF
Low range
Given: Rated Capacitance 2.2 µF, Derating Factor 25 %
Result: Effective Capacitance = 0.55 µF
Typical
Given: Rated Capacitance 0.22 mF, Derating Factor 50 %
Result: Effective Capacitance = 110 µF
High range
Given: Rated Capacitance 2.2 mF, Derating Factor 0.8
Result: Effective Capacitance = 1.76 mF
Maximum range
Given: Rated Capacitance 22 mF, Derating Factor 8
Result: Effective Capacitance = 0.176 F
Solving for each variable
Solve for Effective Capacitance
Rated Capacitance 0.22 µF, Derating Factor 2.5 % → 5.5 nF
Solve for Rated Capacitance
Effective Capacitance 100 nF, Derating Factor 2.5 % → 4 µF
Solve for Derating Factor
Effective Capacitance 100 nF, Rated Capacitance 0.22 µF → 45.45 %
How Effective Capacitance changes with Rated Capacitance
| Rated Capacitance (input) | Effective Capacitance (result) |
|---|---|
| 22 µF | 11 µF |
| 55 µF | 27.5 µF |
| 110 µF | 55 µF |
| 0.165 mF | 82.5 µF |
| 0.22 mF | 110 µF |
| 0.33 mF | 0.165 mF |
| 0.44 mF | 0.22 mF |
| 0.88 mF | 0.44 mF |
| 1.54 mF | 0.77 mF |
| 2.2 mF | 1.1 mF |
The same result in other units
| Unit | Value |
|---|---|
| nF | 110000 |
| µF | 110 |
| mF | 0.11 |
| F | 0.00011 |
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<p><a href="https://vbatpower.com/formulas/ceramic-voltage-derating/">Ceramic Capacitor Voltage Derating</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Ceramic Capacitor Voltage Derating?
Use C_eff = C_rated × derating_factor. With Rated Capacitance 0.22 mF, Derating Factor 50 %, Effective Capacitance works out to 110 µF.
How do you calculate ceramic capacitor derating factor?
Rearrange for Effective Capacitance: with Rated Capacitance 2.2 µF, Derating Factor 25 %, Effective Capacitance is 0.55 µF.
How do you calculate 75v ceramic derating at 60v?
Rearrange for Effective Capacitance: with Rated Capacitance 0.22 mF, Derating Factor 50 %, Effective Capacitance is 110 µF.
What is the formula for Ceramic Capacitor Voltage Derating?
The formula is C_eff = C_rated × derating_factor. Class II and Class III ceramic capacitors (X7R, X5R, Y5V, Z5U) lose significant capacitance when a DC bias voltage is applied.
How do you find Rated Capacitance when you know the other values?
Rearrange for Rated Capacitance: with Effective Capacitance 100 nF, Derating Factor 2.5 %, Rated Capacitance is 4 µF.
How do you find Derating Factor when you know the other values?
Rearrange for Derating Factor: with Effective Capacitance 100 nF, Rated Capacitance 0.22 µF, Derating Factor is 45.45 %.
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