Convert kinematic viscosity between m²/s, stokes, centistokes and ft²/s.
Fluids • 6 units
All 6 units on the Kinematic Viscosity Converter are defined against the Meter²/second (m²/s), so each result is one conversion factor away from a single reference rather than the end of a chain of roundings.
The conversion this page is most often opened for is ready before you type anything: 1 m²/s = 1,000,000 cSt. Change either side and every row in the table recalculates with it.
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The SI unit here is enormous relative to anything that flows: 1 m²/s is 1,000,000 centistokes, and no ordinary liquid comes near it. That is why the working rows are the small ones, and why the table contains a free identity worth knowing — the square millimetre per second and the centistoke are the same quantity exactly, so a datasheet quoting mm²/s and one quoting cSt can be compared without touching a calculator.
Engine-oil grades encode two different measurements in one label, and only one of them belongs on this page. In a 5W-30, the second number is a kinematic viscosity band measured at 100 °C in centistokes, while the number before the W comes from low-temperature cranking and pumping tests that are reported in dynamic units, not kinematic ones. A multigrade is therefore not a single viscosity at all but a pair of limits at opposite ends of the temperature range, which is why two oils sharing a grade can behave differently in between.
Older American datasheets sometimes quote Saybolt Universal Seconds, an efflux time measured by draining a fixed volume through a standard orifice. It is deliberately absent from this table because it is not convertible by a single factor: the relationship to centistokes is non-linear near the low end and only settles into a near-constant ratio of roughly 4.6 cSt per second well above 70 SUS. Converting a Saybolt figure requires the published conversion table for the relevant range, not multiplication.
Quick reference — 1 Meter²/second (m²/s) is equal to:
| Stokes | St | 10,000 |
| Centistokes | cSt | 1,000,000 |
| Millimeter²/second | mm²/s | 1,000,000 |
| Centimeter²/second | cm²/s | 10,000 |
| Foot²/second | ft²/s | 10.763910 |
6 units of kinematic viscosity, each a fixed multiple of the m²/s. The table spans 1,000,000:1, from cSt (0.000001 m²/s) to m²/s (1 m²/s). Conversion is one multiplication into the base unit and one division out of it, with no lookup table and no approximation.
value_to = value_from × (factor_from ÷ factor_to)1 m²/s = 1 m²/s1 St = 0.0001 m²/s1 cSt = 0.000001 m²/s1 mm²/s = 0.000001 m²/s1 cm²/s = 0.0001 m²/s1 ft²/s = 0.092903 m²/swhere:
Assumptions: Factors are exact definitions. Full double precision is carried internally and rounding is applied only for display.
Result25 m²/s = 25000000 cSt
Kinematic viscosity is dynamic viscosity divided by density, giving units of square metres per second (m²/s). It is the form that appears in fluid-flow equations, because what governs whether flow is smooth or turbulent is viscosity relative to inertia, not viscosity alone.
The practical unit is the centistoke, 10⁻⁶ m²/s, chosen so that water at 20 °C is almost exactly 1 cSt. Lubricant grades are built directly on it: ISO VG 46 oil is 46 cSt at 40 °C. That temperature reference is not optional — viscosity falls steeply as oil warms, so a grade quoted without its reference temperature is meaningless, which is the single most common misreading of an oil datasheet.