Device physicsMVP
Parallel-plate capacitor
Capacitance of an ideal parallel-plate capacitor from plate area, spacing, and dielectric.
Inputs
Result
Enter values and calculate to see the result.
Interpretation
Enter the plate area, spacing, and dielectric constant.
Formula
C = ε₀ · εr · A / d
ε₀ = vacuum permittivity.
Variables
| Symbol | Variable | Unit |
|---|---|---|
| C | Capacitance | F (shown as pF/nF) |
| ε₀ | Vacuum permittivity | F/m (8.854×10⁻¹²) |
| εr | Relative permittivity | dimensionless |
| A | Plate area | m² |
| d | Plate spacing | m |
Assumptions & validity
This tool assumes:
- Ideal parallel plates; uniform dielectric; ignores fringing fields.
Worked example
A = 1 mm², d = 100 nm, εr = 3.9 (SiO₂).
C = ε₀·3.9·1e-6/1e-7 ≈ 345 pF