Dielectric Constant Calculator
Calculate the relative permittivity (dielectric constant κ), electric susceptibility (χe), and capacitance gain. Includes interactive molecular dipole polarization and a comprehensive material database.
κ = C / C₀
Dielectric Materials Reference Database
Click 'Load Material' to instantly import into the calculator.
| Material Name | Category | Dielectric Const (κ) | Loss Tangent (tan δ) | Breakdown (kV/mm) | Action |
|---|---|---|---|---|---|
| Vacuum | Reference | 1 | 0.0 | ∞ (Vacuum) | |
| Air (Dry, STP) | Gas | 1.00059 | < 0.0001 | 3 kV/mm | |
| PTFE / Teflon | Polymer | 2.1 | 0.0002 | 60 kV/mm | |
| Polyethylene (PE) | Polymer | 2.25 | 0.0003 | 22 kV/mm | |
| Polystyrene (PS) | Polymer | 2.5 | 0.0004 | 24 kV/mm | |
| Transformer Oil | Liquid | 2.2 | 0.001 | 12 kV/mm | |
| Paper (Kraft) | Cellulose | 3.7 | 0.008 | 16 kV/mm | |
| FR-4 PCB Substrate | Composite | 4.4 | 0.02 | 20 kV/mm | |
| Silicon Dioxide (SiO₂) | Semiconductor | 3.9 | 0.0005 | 1000 kV/mm | |
| Pyrex Glass | Glass | 4.7 | 0.005 | 14 kV/mm | |
| Mica (Ruby) | Mineral | 5.4 | 0.0003 | 118 kV/mm | |
| Alumina (Al₂O₃ 99%) | Ceramic | 9.8 | 0.0001 | 17 kV/mm | |
| Silicon (Intrinsic) | Semiconductor | 11.7 | 0.001 | 30 kV/mm | |
| Tantalum Pentoxide (Ta₂O₅) | Oxide | 25 | 0.005 | 450 kV/mm | |
| Pure Water (20°C) | Polar Liquid | 80.4 | 0.04 | 3 kV/mm | |
| Barium Titanate (BaTiO₃) | Ferroelectric | 1250 | 0.015 | 8 kV/mm |
What is the Dielectric Constant (Relative Permittivity)?
The dielectric constant (also termed relative permittivity and designated by the symbol \(\kappa\) or \(\varepsilon_r\)) is a fundamental dimensionless physical property that quantifies the ability of an insulating substance to store electrical energy in an electrostatic field relative to a vacuum.
When an external electric field is applied across a dielectric insulator, bound positive and negative molecular charges undergo microscopic spatial displacement—a phenomenon called dielectric polarization. These induced dipoles generate an internal counter-field that partially cancels the external field, reducing the net field and allowing capacitors to store substantially higher charges for any given voltage.
How to Use the Dielectric Constant Calculator
Calculate permittivity and evaluate insulation materials across three distinct engineering modes.
Select Calculation Mode
Choose between Capacitance Ratio (C/C₀), Physical Dimensions (C, A, d), or Field Reduction (E₀/E).
Enter Parameters
Input measured test capacitance in pF, plate geometry, or field values using the responsive sliders.
Inspect Dipole Alignment
Observe real-time molecular orientation and opposing bound surface charge cancellation on the canvas.
Explore Material Library
Compare polymers, semiconductors, glasses, and high-κ ferroelectrics directly from the interactive table.
Key Engineering Features
Built for electrical engineers, materials scientists, and physics researchers.
Multi-Mode Formulation
Seamlessly calculate dielectric constant from direct laboratory impedance or electrostatic field measurements.
Extensive Material Library
Searchable reference database including loss tangents (tan δ) and dielectric breakdown ratings in kV/mm.
Electric Susceptibility
Directly computes electric susceptibility (χe = κ - 1) and absolute permittivity (ε = κε₀) in F/m.
Governing Dielectric Equations
The relative dielectric constant \(\kappa\) is defined as the ratio of absolute material permittivity \(\varepsilon\) to vacuum permittivity \(\varepsilon_0\):
The electric susceptibility χ_e defines the degree of dielectric polarization P in response to an electric field E:
The electric displacement field D combines the free electric field and bound polarization:
Real-World Engineering Applications
Multi-Layer Ceramic Capacitors (MLCC)
Modern smartphones contain over 1,000 MLCCs. By incorporating high-κ ceramics such as Barium Titanate (κ > 1,200) interleaved between microscopic nickel electrodes, manufacturers achieve capacitance up to 100 µF in packaging smaller than a grain of sand.
High-Speed PCB Substrates & Transmission Lines
In multi-gigahertz digital circuits, high dielectric constants slow down signal propagation velocity (v = c / √κ) and increase dielectric loss. High-speed designers select ultra-low-κ PTFE or Rogers laminates to preserve high-frequency signal integrity.
Frequently Asked Questions
The terms 'dielectric constant' and 'relative permittivity' (represented by κ or εr) refer to the exact same physical dimensionless property: the ratio of the permittivity of a substance to the permittivity of free space (ε / ε₀).
For polar dielectrics (such as water or ethanol), the dielectric constant decreases with increasing temperature because thermal agitation disrupts the alignment of molecular dipoles with the external electric field.
Electric susceptibility (χe = κ - 1) is a dimensionless measure of how easily a dielectric material polarizes in response to an applied electric field. It defines the induced polarization P = ε₀ * χe * E.
Barium Titanate (BaTiO₃) is a ferroelectric material exhibiting an exceptionally high dielectric constant (κ between 1,200 and 10,000+), allowing multi-layer ceramic capacitors (MLCCs) to achieve microfarad capacitances in tiny surface-mount footprints.