CGS System of Units Converter
With this CGS system of units converter, you can quickly convert CGS units to SI units and vice versa. Essential for physics, astronomy, and engineering students.
What is the CGS system of units?
The CGS (centimeter-gram-second) system is a metric system of measurement where the base units are the centimeter for length, gram for mass, and second for time. Developed in the 19th century, it was the predecessor to the MKS (meter-kilogram-second) system and the modern SI system. CGS units are still used in some specialized scientific fields: astronomy (star luminosities in erg/s), astrophysics (magnetic fields in gauss), chemistry (concentrations in g/cm³), and electromagnetism (using Gaussian units). Key CGS units include the dyne (force), erg (energy), poise (viscosity), gauss (magnetic flux density), and barye (pressure).
How do I convert CGS units to SI units?
Converting CGS to SI requires these multiplication factors: Length: cm to m × 0.01 (1 cm = 0.01 m). Mass: g to kg × 0.001 (1 g = 0.001 kg). Force: dyne to N × 0.00001 (1 dyne = 10⁻⁵ N). Energy: erg to J × 0.0000001 (1 erg = 10⁻⁷ J). Pressure: barye to Pa × 0.1 (1 barye = 0.1 Pa). Dynamic viscosity: poise to Pa·s × 0.1 (1 poise = 0.1 Pa·s). Kinematic viscosity: stokes to m²/s × 0.0001 (1 St = 10⁻⁴ m²/s). Magnetic field: gauss to tesla × 0.0001 (1 G = 10⁻⁴ T). These factors are all powers of 10, making conversion systematic.
Why is the CGS system still used in some scientific fields?
The CGS system persists in some scientific fields for historical and practical reasons: Astronomy: stellar luminosities are traditionally measured in ergs/s because the numbers are more manageable (solar luminosity = 3.828 × 10³³ erg/s). Electrodynamics: Gaussian CGS units simplify Maxwell's equations by making the speed of light appear explicitly. Astrophysics: magnetic fields in gauss are more intuitive than tesla (1 tesla = 10,000 gauss). Chemistry: concentrations in g/cm³ and g/mL are intuitive. However, most modern scientific work has switched to SI, and CGS is primarily used in legacy contexts and specialized research areas.
What are the key CGS units I should know?
Essential CGS units and their SI equivalents: Length: centimeter (cm) — 1 cm = 0.01 m. Mass: gram (g) — 1 g = 0.001 kg. Force: dyne (dyn) — 1 dyn = 10⁻⁵ N (force needed to accelerate 1 g at 1 cm/s²). Energy: erg — 1 erg = 10⁻⁷ J (work done by 1 dyne over 1 cm). Pressure: barye (Ba) — 1 Ba = 0.1 Pa = 0.1 N/m². Dynamic viscosity: poise (P) — 1 P = 0.1 Pa·s. Kinematic viscosity: stokes (St) — 1 St = 10⁻⁴ m²/s. Magnetic flux density: gauss (G) — 1 G = 10⁻⁴ T. Luminosity: erg/s — 1 erg/s = 10⁻⁷ W. These cover the most common CGS to SI conversions needed in physics and engineering.