G sets the strength of gravity between any two masses. It is the same everywhere in the universe, unlike g, which changes with height and place.
Value of G in different units
| Value | Use it when |
|---|---|
| 6.674 × 10⁻¹¹ N m² kg⁻² | SI. |
| 6.67 × 10⁻¹¹ N m² kg⁻² | The rounded value in most questions. |
| 6.674 × 10⁻⁸ dyn cm² g⁻² | CGS. |
Formulas that use G
- F = Gm₁m₂/r²
- g = GM/R²
- vₑ = √(2GM/R)
- T² = (4π²/GM) r³
Its dimensional formula is worked out on the dimensional formula of gravitational constant G page.
Other constants
- Gas constant (R): 8.314 J mol⁻¹ K⁻¹
- Planck's constant (h): 6.626 × 10⁻³⁴ J s
- Avogadro's number (Nₐ): 6.022 × 10²³ mol⁻¹
- Speed of light (c): 3 × 10⁸ m/s
- Charge of an electron (e): 1.602 × 10⁻¹⁹ C
- Mass of an electron (mₑ): 9.109 × 10⁻³¹ kg
- Mass of a proton (mₚ): 1.673 × 10⁻²⁷ kg
- Mass of a neutron (mₙ): 1.675 × 10⁻²⁷ kg
- Universal gravitational constant (G): 6.674 × 10⁻¹¹ N m² kg⁻²
- Acceleration due to gravity (g): 9.8 m/s²
- Boltzmann constant (k): 1.381 × 10⁻²³ J/K
- Faraday constant (F): 96 485 C/mol
- Permittivity of free space (ε₀): 8.854 × 10⁻¹² C² N⁻¹ m⁻²
- Permeability of free space (μ₀): 4π × 10⁻⁷ T m/A
- Rydberg constant (R): 1.097 × 10⁷ m⁻¹
- Stefan–Boltzmann constant (σ): 5.67 × 10⁻⁸ W m⁻² K⁻⁴
- Wien's constant (b): 2.898 × 10⁻³ m K
- Bohr radius (a₀): 0.529 Å
- Molar volume of a gas at STP (Vₘ): 22.4 L/mol
The full list, searchable, is on the physical constants page.
Questions students ask
What is the value of universal gravitational constant?
G = 6.674 × 10⁻¹¹ N m² kg⁻². In other units: 6.674 × 10⁻¹¹ N m² kg⁻²; 6.67 × 10⁻¹¹ N m² kg⁻²; 6.674 × 10⁻⁸ dyn cm² g⁻².
What is G in physics and chemistry?
G sets the strength of gravity between any two masses. It is the same everywhere in the universe, unlike g, which changes with height and place.
Which value of G should I use?
6.674 × 10⁻¹¹ N m² kg⁻²: SI. 6.67 × 10⁻¹¹ N m² kg⁻²: The rounded value in most questions. 6.674 × 10⁻⁸ dyn cm² g⁻²: CGS.
What is the dimensional formula of universal gravitational constant?
See the dimensional formula of universal gravitational constant, worked out step by step on its own page.