Physical Constants Library
Searchable reference of fundamental physical constants with NIST/CODATA values.
| Name | Symbol | Value | Unit | Source |
|---|---|---|---|---|
| Speed of Light | c | 299,792,458 | m/s | NIST |
| Planck Constant | h | 6.626 070 15 × 10⁻³⁴ | J·s | CODATA 2018 |
| Gravitational Constant | G | 6.674 30 × 10⁻¹¹ | m³/(kg·s²) | CODATA 2018 |
| Boltzmann Constant | k_B | 1.380 649 × 10⁻²³ | J/K | NIST |
| Elementary Charge | e | 1.602 176 634 × 10⁻¹⁹ | C | NIST |
| Avogadro Number | N_A | 6.022 140 76 × 10²³ | mol⁻¹ | NIST |
| Gas Constant | R | 8.314 462 618 | J/(mol·K) | CODATA 2018 |
| Electron Mass | m_e | 9.109 383 7015 × 10⁻³¹ | kg | CODATA 2018 |
| Proton Mass | m_p | 1.672 621 923 69 × 10⁻²⁷ | kg | CODATA 2018 |
| Stefan-Boltzmann Constant | σ | 5.670 374 419 × 10⁻⁸ | W/(m²·K⁴) | NIST |
| Standard Atmosphere | atm | 101,325 | Pa | BIPM |
| Standard Gravity | g | 9.806 65 | m/s² | BIPM |
Cite this page
UnitConvertLab. (2026). Physical Constants Library. UnitConvertLab. Retrieved from https://unitconvertlab.com/reference/constants