The CGS system of units converter is useful for finding relationships between SI units and the most often used CGS units. A system of measuring is a collection of units and the rules that link them. Many measuring methods have been established during the course of human history, for example:
- The metric system of units (meters, kilograms, seconds) or the International System of Units
- (SI), the imperial system of units (foot and pound),
- CGS system of units (centimeter – gram – second).
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What is cgs system of units?
The centimetre–gram–second (abbreviated CGS or cgs) system of units is a variation of the metric system that uses the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units are explicitly derived from these three foundation units, however, the CGS system was expanded in a variety of ways to include electromagnetism.
The CGS system was substantially superseded by the MKS system, which was extended and replaced by the International System of Units, which was based on the metre, kilogram, and second (SI). SI is the sole system of units used in many sectors of research and engineering, while CGS is still widely used in several subfields. The differences between CGS and SI in measurements of purely mechanical systems (including units of length, mass, force, energy, pressure, and so on) are clear and minor; the unit-conversion factors are all powers of ten, such as 100 cm = 1 m and 1000 g = 1 kg.
Converting between CGS and SI is more delicate in measurements of electromagnetic phenomena (involving units of charge, electric and magnetic fields, voltage, and so on). The form of formulas for physical laws of electromagnetic (such as Maxwell’s equations) varies depending on the unit system utilized. This is due to the fact that electromagnetic values in SI and CGS are defined differently, but mechanical quantities are defined the same way. Furthermore, there are multiple viable methods to define electromagnetic quantities inside CGS, resulting in several “sub-systems,” such as Gaussian units, “ESU,” “EMU,” and Lorentz–Heaviside units. Gaussian units are the most used today, and the term “CGS units” is commonly used to refer to CGS-Gaussian units.
CGS units in mechanics and tables
The quantities in the CGS and SI systems are defined identically in mechanics. Only the scale of the three basic units (centimetre vs metre and gram versus kilogram, respectively) differs between the two systems. The third unit (second) is the same in each.
The base units of mechanics in CGS and SI have a clear connection. Because both systems have the same equations for expressing the laws of physics and are coherent, the definitions of all coherent derived units in terms of the base units are the same in both systems, and there is an unambiguous correspondence of derived units:
| Quantity | Quantity symbol | CGS unit name | Unit symbol | Unit definition | In coherent SI units |
| length, position | L, x | centimetre | cm | 1/100 of metre | 10−2 m |
| mass | m | gram | g | 1/1000 of kilogram | 10−3 kg |
| time | t | second | s | 1 second | 1 s |
| velocity | v | centimetre per second | cm/s | cm/s | 10−2 m/s |
| acceleration | a | gal | Gal | cm/s2 | 10−2 m/s2 |
| force | F | dyne | dyn | g⋅cm/s2 | 10−5 N |
| energy | E | erg | erg | g⋅cm2/s2 | 10−7 J |
| power | P | erg per second | erg/s | g⋅cm2/s3 | 10−7 W |
| pressure | p | barye | Ba | g/(cm⋅s2) | 10−1 Pa |
| dynamic viscosity | μ | poise | P | g/(cm⋅s) | 10−1 Pa⋅s |
| kinematic viscosity | ν | stokes | St | cm2/s | 10−4 m2/s |
| wavenumber | k | kayser (K) | cm−1 | cm−1 | 100 m−1 |
Unit of acceleration in cgs system
C.G.S unit of acceleration = 1 cm/s2. M.K.S. unit of acceleration = 1m/s2.
The gal (symbol: Gal) is a unit of acceleration that is sometimes used in gravimetry. It is named after Galileo Galilei. 1 centimeter per second squared (1 cm/s2) is the definition of a gal. The milligal (mGal) and microgal (Gal) are one thousandth and one-millionth of a gallon, respectively.
The gal is not a unit of measurement in the International System of Units (SITU) (known by its French-language initials “SI”). The CIPM concluded in 1978 that the gal may be used “with the SI until the CIPM deems usage is no longer required.” On the other hand, the gal is discouraged by ISO 80000-3:2006.
Unit of force in cgs system
S.I. unit of force is the newton, C.G.S. unit of force is dyne.
The dyne is a derived unit of force in the centimetre–gram–second (CGS) units, which is a forerunner to the present SI. A committee of the British Association for the Advancement of Science recommended the word dyne as a CGS unit of force in 1873. “The force necessary to accelerate a mass of one gram at a velocity of one millimeter per second squared,” says the dyne. The dyne may also be defined as “that force that, when operating for one second, causes a change in velocity of one centimetre per second in a mass of one gram.”
Unit of energy in cgs system
Unit of energy is joule J and C.G.S. unit is erg.
The erg is a unit of energy that equals 10-7 joules (100 nJ). Its origins may be traced back to the centimetre–gram–second (CGS) unit system. The symbol for it is erg. The erg isn’t a standard SI unit. Its name comes from the Greek word ergon, which means ‘labor’ or ‘job.’ An erg is the amount of work performed by a force of one dyne applied across a one-centimetre distance. It is equivalent to one gram centimetre-squared per second-squared in CGS base units. In SI terms, it equals 10-7 joules or 100 nanojoules (nJ). An erg is the amount of labor (or energy) done (or spent) by one common house fly completing one “push up,” or the leg-bending dip that takes its mouth to the surface on which it stands and then back up.
Unit of pressure in cgs system
The bar is the C.G.S. unit of pressure.
A bar is defined as the pressure produced on a 1 cm2 area by a force of 1 dyne. The centimetre–gram–second (CGS) unit of pressure is the barye (symbol: Ba), sometimes known as barad, barrie, bary, baryd, baryed, or barie. 1 dyne per square cm is the unit.
Unit of dynamic viscosity in cgs system
The poise (P), named after Jean Poiseuille, is the physical unit representing dynamic viscosity in the centimeter gram second system of units (cgs). It’s more generally referred to as centipoise, especially in ASTM standards (cP).
Unit of kinematic viscosity in cgs system
The CGS unit centistokes is commonly used to quantify kinematic viscosity (cSt).
The square meter per second (m2/s) is the SI unit for kinematic viscosity, whereas the stokes, named for Sir George Gabriel Stokes, is the CGS unit. The single form of stroke is sometimes used in the United States. Instead, submultiple centistokes (cSt) are frequently utilized. At 20 °C, water has a kinematic viscosity of roughly 1 cSt.
Unit of charge in cgs system
The “electrostatic unit,” or esu, is the cgs unit for electric charge. The esu’s size is chosen to ensure that the constant in Coulomb’s force law is one. As a result, there are two charges, each with a charge. 1 esu sitting 1 cm apart will experience a force of 1 dyne between them.
Unit of voltage in cgs system
In the CGS-ESU and gaussian systems of units, the statvolt is a voltage and electrical potential unit. In terms of SI units, one statvolt equals precisely ccgs 10-8 volt, or 299.792458 volts. The statvolt is also known as 1 erg / statcoulomb in the CGS system.
Unit of magnetic b field in cgs system
The Gauss (Gs or G) is a CGS unit for measuring the magnetic field B, commonly known as magnetic flux density or magnetic induction. The unit of Gauss is one Maxwell per square cm. Gauss is the CGS unit for magnetic field strength.
Unit of magnetic h field in cgs system
The fraction of the magnetic field in a material that derives from an external current and is not intrinsic to the material itself is known as magnetic field strength, also known as magnetic intensity or magnetic field intensity. It is measured in amperes per metre and is given as the vector H.
CGS units in electromagnetism
The conversion factors for electromagnetic units are more difficult in the CGS and the International System of Units. This is due to discrepancies in how electromagnetism’s physical rules are expressed. You may find relationships between electromagnetic units of the International System of Units and the Gaussian CGS system in this CGS system of units converter.
| Quantity (symbol) | Gaussian CGS unit name (symbol) | Equivalent in SI units |
| charge (q) | franklin (Fr) | 3.336 * 10¹⁰ C |
| voltage (V) | statvolt (statV) | 299.8 V |
| magnetic B field (B) | gauss (G) | 10⁻³ T |
| magnetic H field (H) | oersted (Oe) | 79.577 A/m |
Physical constants in CGS units and MKS units
Physical constants are visibly affected by differences between metric and CGS units.
| Constant (symbol) | Value – SI units | Value – Gaussian CGS units |
| Atomic mass unit (u) | 1.66*10⁻²⁷ kg | 1.66*10⁻²⁴ g |
| Bohr magneton (μB) | 9.27*10⁻²⁴ J/T | 9.27*10⁻²¹ erg/G |
| Bohr radius (a0) | 5.29*10⁻¹¹ m | 5.29*10⁻⁹ m |
| Boltzmann constant (kB) | 1.38*10⁻²³ J/K | 1.38*10⁻¹⁶ erg/K |
| Electron mass (me) | 9.11*10⁻³¹ kg | 9.11*10⁻²⁸ g |
| Elementary charge (e) | 1.6*10⁻¹⁹ C | 4.8*10⁻¹⁰ Fr |
| Fine-structure constant (α) | 1/137 | 1/137 |
| Gravitational constant (G) | 6.67*10⁻¹¹ N*m²/kg² | 6.67*10⁻⁸ dyn*cm²/g² |
| Planck constant (h) | 6.626*10⁻³⁴ J*s | 6.626*10⁻²⁷ erg*s |
| Speed of light in vacuum (c) | 2.998*10⁸ m/s | 2.998*10¹⁰ cm/s |
How to use our calculator and what calculates
Here are a few steps that you need to follow to correctly use our CGS System of Units Converter:
- As a fraction, write the conversion (that equals one)
- Multiply the result (leaving all units in the answer)
- Cancel any units that are both at the top and bottom of the stack.
