Kinematic viscosity converter
Convert between centistokes and m²/s, the numbers on oil datasheets and ISO viscosity grades.
That's about the same as SAE 30 oil. That is about 100× as thick as water.
What it means
How thick is that?
Oil grades such as ISO VG 46 are the kinematic viscosity in cSt at 40 °C. Viscosity falls sharply as oil warms.
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Your viscosity in every unit
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Three things worth knowing
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ISO VG is just cSt at 40 °C
ISO VG 46 hydraulic oil measures 46 cSt at 40 °C. The grade is the measurement, with no code to decipher.
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Stokes and falling spheres
George Stokes worked out how spheres fall through fluids. The unit named after him is still measured by timing how long oil takes to drain through a calibrated tube.
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cSt is not cP
Centistokes and centipoise are only equal for fluids with the density of water. For oil at 0.87 g/cm³ the two differ by 13%.
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Background
About kinematic viscosity
Kinematic viscosity is dynamic viscosity divided by density, in m²/s. The practical unit is the centistoke, chosen so water sits at almost exactly 1 cSt.