CGS System of Units Converter

Convert SI and CGS units for ten physical quantities.

Covers acceleration, force, energy, pressure, viscosity, charge, voltage, and magnetic fields with selectable SI units.

Updated August 19, 2026

CreatorFrank Zhao

Loading calculator…

Introduction / Overview

What is this converter?

The CGS System of Units Converter translates values between two major families of physical units: the SI (International System of Units), used universally in engineering and commerce, and the CGS (centimeter-gram-second) system, which remains common in theoretical physics and laboratory research.

Many textbooks, journal articles, and legacy datasets express quantities in CGS units — gals for acceleration, dynes for force, ergs for energy, poise for viscosity, and gauss for magnetic fields. This calculator lets you enter a value in either system and instantly see the equivalent in the other, with bidirectional support for every quantity it covers.

Supported quantities

1Acceleration

2Force

3Energy

4Pressure

5Dynamic viscosity

6Kinematic viscosity

7Electric charge

8Voltage

9Magnetic B field

10Magnetic H field

Every conversion factor in this calculator is an exact mathematical constant. No approximations or rounding are applied to the underlying values.

How to Use / Quick Start

Select the quantity

Open the "Conversion type" dropdown and choose the physical quantity you want to convert — for example, Charge or Magnetic B field.

Enter a value in either field

Type a number in the SI field or the CGS field. The other field updates automatically. You can switch between input units using the unit dropdown on the SI field where available.

Read the result

The derived field shows the converted value in the other system. Blue text indicates a derived (auto-calculated) result.

eExample: Converting electric charge

Suppose a physics paper reports a charge of 1 franklin (Fr). Convert it to coulombs:

q_{\mathrm{SI}} = \frac{q_{\mathrm{CGS}}}{2\,997\,924\,580}

=

\frac{1\ \mathrm{Fr}}{2\,997\,924\,580}

\approx

3.336 \times 10^{-10}\ \mathrm{C}

One franklin equals approximately $3.34 \times 10^{-10}$ coulombs. This factor comes from the definition of the speed of light in CGS: $c = 2.997\,924\,58 \times 10^{10}\ \mathrm{cm/s}$ .

Conversion Factors Reference

Every factor below is exact. The six mechanical quantities use powers of ten that arise directly from the definitions of CGS base units (centimeter, gram, second). The four electromagnetic quantities involve fundamental constants — the speed of light $c$ and $\pi$ .

Mechanical Quantities

Quantity	CGS Unit	SI Unit	SI = CGS ×	Note
Acceleration	Gal	m/s²	$\mathrm{SI} = \mathrm{CGS} \times 10^{-2}$	1 Gal = 0.01 m/s²
Force	dyn	N	$\mathrm{SI} = \mathrm{CGS} \times 10^{-5}$	1 dyn = 1e-5 N
Energy	erg	J	$\mathrm{SI} = \mathrm{CGS} \times 10^{-7}$	1 erg = 1e-7 J
Pressure	Ba	Pa	$\mathrm{SI} = \mathrm{CGS} \times 10^{-1}$	1 Ba = 0.1 Pa
Dynamic viscosity	P	kg/(m·s)	$\mathrm{SI} = \mathrm{CGS} \times 10^{-1}$	1 P = 0.1 kg/(m·s)
Kinematic viscosity	St	m²/s	$\mathrm{SI} = \mathrm{CGS} \times 10^{-4}$	1 St = 1e-4 m²/s

Electromagnetic Quantities

Quantity	CGS Unit	SI Unit	SI = CGS ×	Note
Electric charge	Fr	C	$\mathrm{SI} = \mathrm{CGS} \times \frac{1}{2.99792458 \times 10^9}$	Exact, from speed of light
Voltage	statV	V	$\mathrm{SI} = \mathrm{CGS} \times 299.792458$	Exact, from speed of light
Magnetic B field	G	T	$\mathrm{SI} = \mathrm{CGS} \times 10^{-3}$	1 G = 1e-3 T
Magnetic H field	Oe	A/m	$\mathrm{SI} = \mathrm{CGS} \times \frac{250}{\pi}$	1 Oe = 250/π A/m

For the six mechanical quantities, the CGS-to-SI factor is always a power of ten. This is because CGS and SI share the same dimensional structure (mass × length / time² for force, etc.) but differ in the scale of the centimeter versus the meter and the gram versus the kilogram.

The four electromagnetic quantities (charge, voltage, magnetic B, magnetic H) have factors that depend on the choice of CGS subsystem. This calculator uses the Gaussian CGS convention, which is the most widely used in theoretical electromagnetism. In Gaussian CGS, the speed of light $c$ and $\pi$ appear explicitly in the conversion factors.

Limitations

CGS subsystem

The electromagnetic conversion factors (charge, voltage, magnetic B, magnetic H) use the Gaussian CGS convention. Other CGS subsystems — electrostatic (ESU/CGS) and electromagnetic (EMU/CGS) — define these quantities differently. If your source uses ESU or EMU, the factors in this table may not apply directly.

Unit scope

The CGS field for each quantity shows only the base CGS unit (e.g., Gal, dyn, erg) plus the CGS sub-units listed (poise/centipoise for dynamic viscosity, stokes/centistoke for kinematic viscosity). The SI field offers a selection of SI sub-units. Additional SI or CGS sub-units not listed here can be derived by multiplying or dividing by the appropriate power of ten.

Pure conversion only

This tool converts a single numeric value between two unit systems. It does not combine quantities, apply physical models, or validate whether the resulting value is physically meaningful in a given context. For calculations involving multiple quantities or physical constraints, use a dedicated physics calculator.

Related Calculators

Text to NATO alphabet

Transform text into the NATO phonetic alphabet for oral transmission. Convert letters A–Z into Alpha/Bravo/Charlie… and copy instantly.

Try Now

Text to ASCII binary

Convert text to ASCII (8-bit) binary and convert ASCII binary back to text. Clean input automatically and copy results instantly.

Try Now

Text to Unicode

Convert text to Unicode decimal HTML entities (e.g., A) and convert them back to text. Runs locally in your browser with one-click copy.

Try Now

Escape/unescape HTML entities

Escape and unescape HTML entities for <, >, &, ", and ’. Runs locally in your browser with instant copy.

Try Now

Integer Base Converter

Convert an integer between bases 2–64 (binary, octal, decimal, hexadecimal, base64, and custom). Runs locally in your browser.

Try Now

Base64 String Encoder/Decoder

Encode text to Base64 and decode Base64 back to text. Supports URL-safe Base64. Runs locally in your browser with instant copy.

Try Now