Physics Constant Finder icon

Physics Constant Finder

Instantly search and access over 15+ fundamental physics and universal constants. Ideal for students, researchers, and engineers.

Search Constants
Find constants by name, symbol, or category.
Speed of Light in Vacuum(c)
Universal
2.9979e+8
Unit: m/s

The speed at which light waves propagate through a vacuum.

Planck Constant(h)
Quantum Mechanics
6.6261e-34
Unit: J⋅s

A fundamental constant characterizing the quantization of energy.

Reduced Planck Constant(ħ)
Quantum Mechanics
1.0546e-34
Unit: J⋅s

Planck constant divided by 2π, also known as Dirac constant.

Gravitational Constant(G)
Gravitation
6.6743e-11
Unit: m³/(kg⋅s²)

Empirical physical constant involved in the calculation of gravitational force between two bodies.

Elementary Charge(e)
Electromagnetism
1.6022e-19
Unit: C

The electric charge carried by a single proton.

Electron Mass(mₑ)
Particle Physics
9.1094e-31
Unit: kg

The stationary mass of an electron.

Proton Mass(mₚ)
Particle Physics
1.6726e-27
Unit: kg

The rest mass of a proton.

Neutron Mass(mₙ)
Particle Physics
1.6749e-27
Unit: kg

The rest mass of a neutron.

Boltzmann Constant(k)
Thermodynamics
1.3806e-23
Unit: J/K

Relates the average kinetic energy of particles in a gas with the temperature of the gas.

Avogadro Constant(Nₐ)
Chemistry
6.0221e+23
Unit: mol⁻¹

The number of constituent particles (usually atoms or molecules) that are contained in the amount of substance given by one mole.

Gas Constant(R)
Thermodynamics
8.314462618
Unit: J/(mol⋅K)

Equivalent to the Boltzmann constant, but expressed in units of energy per temperature increment per mole.

Stefan-Boltzmann Constant(σ)
Thermodynamics
5.6704e-8
Unit: W/(m²⋅K⁴)

Physical constant describing the power radiated from a black body in terms of its temperature.

Fine-Structure Constant(α)
Electromagnetism
0.0072973525693
Unit: Dimensionless

Characterizes the strength of the electromagnetic interaction between elementary charged particles.

Vacuum Permittivity(ε₀)
Electromagnetism
8.8542e-12
Unit: F/m

Capability of an electric field to permeate a vacuum.

Vacuum Permeability(μ₀)
Electromagnetism
1.2566e-6
Unit: H/m

Measure of the resistance of a material against the formation of a magnetic field.

Standard Gravity(g₀)
Gravitation
9.80665
Unit: m/s²

Standard acceleration due to gravity on Earth.

Rydberg Constant(R∞)
Atomic Physics
1.0974e+7
Unit: m⁻¹

Physical constant relating to the electromagnetic spectra of an atom.

Bohr Magneton(μ_B)
Atomic Physics
9.2740e-24
Unit: J/T

Physical constant in atomic physics expressing the magnetic moment of an electron caused by its orbital or spin angular momentum.

Instantly search and access over 15+ fundamental physics and universal constants. Ideal for students, researchers, and engineers.

How to Use This Physics Constant Finder

  1. 1Use the search bar to find constants by name, symbol, or description.
  2. 2Filter by category to narrow down your results.
  3. 3Click the copy icon to copy the value to your clipboard.
  4. 4Review the symbol, unit, and description for each constant.

Features

  • ✓Search by name, symbol, or description
  • ✓Categorized view (Quantum Mechanics, Thermodynamics, etc.)
  • ✓Exact values with units and symbols
  • ✓Scientific notation display
  • ✓One-click copy to clipboard
  • ✓Mobile-friendly interface

What are Physics Constants?

Physics constants, or universal constants, are quantities that are believed to be both universal in nature and have constant value in time. They are fundamental to the laws of physics and include values like the Speed of Light (c), Planck Constant (h), and Gravitational Constant (G).

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Last Verified: January 2026