Free · CGS and SI units

CGS and SI Unit Pairs with Classical EM Conventions

Convert ten CGS quantity types to SI and back, retaining the original alternate units and explicit classical electromagnetic conventions.

Formula & worked example
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Calculator inputs

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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

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Formula and method

One stokes corresponds to 0.0001 square meters per second.

1 dyn = 10⁻⁵ N; 1 erg = 10⁻⁷ J; 1 St = 10⁻⁴ m²/s; 1 G = 10⁻⁴ T.

Worked example

Enter these known values and leave the other values blank.

Select the type of conversion you need: Kinematic viscosity
CGS: 1 St

SI: 0.0001 m²/s

Assumptions and limitations

Choose one of ten quantity types. Enter a known value on either side, and clear the other to solve backwards. Signed and zero values are accepted; signs describe oriented quantities where meaningful.
Mechanical conversions use the stated CGS definitions. Gal is a galileo, the acceleration unit, and is unrelated to a volume gallon. Barye means dyn/cm². Poise and stokes measure different viscosities.
Electromagnetic choices use the classical electrostatic/Gaussian conventions shown: 1 statC = 1/2997924580 C; 1 statV = 299.792458 V; 1 G = 10⁻⁴ T; 1 Oe = 250/π A/m. Do not interpret all of these as exact measured electromagnetic realizations in the post-2019 SI; the magnetic constant is measured under that SI.
B and H are different quantities. Converting gauss to tesla does not convert B into H, and it does not infer a material permeability. Alternate selector units convert within the selected physical quantity.

Common questions

Does the converter preserve inverse calculations?

Yes. Every captured pair is editable in both directions. Clear the unknown side before entering a known value.

Why disclose the electromagnetic convention?

CGS electromagnetic systems use different definitions. This converter preserves classical electrostatic/Gaussian conversion conventions, with their scope stated explicitly.

References

Use 10^-4 m²/s per stokes and 10^-4 tesla per gauss, correcting captured factors of ten. Use the classical electrostatic convention 299.792458 volts per statvolt instead of rounded 299.8. Preserve the captured classical charge and magnetic-H conventions, both inverse directions, signed and zero values, and every unit selector. Resolve the ten exact dataset-name group macros through pinned source option identities without runtime macro evaluation.

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