Kinematic Viscosity converter
Dynamic viscosity divided by density, the cSt figure printed on lubricant datasheets.
Converter
Quick pairs
tap to loadOne centistokes in every kinematic viscosity unit
6 rows| Unit | Symbol | 1 cSt equals |
|---|---|---|
| Square meter per second | m²/s | 1e-6 |
| Square centimeter per second (stokes) | St | 0.01 |
| Square millimeter per second | mm²/s | 1 |
| Square foot per second | ft²/s | 1.076391042e-5 |
| Square inch per second | in²/s | 0.0015500031 |
| Square foot per hour | ft²/h | 0.0387500775 |
How the centistokes to square meter per second conversion works
Kinematic viscosity is referenced to square meter per second (m²/s), the SI-coherent unit, which equals dynamic viscosity divided by density. Stokes (St) is a cgs-scale unit equal to one ten-thousandth of that, centistokes (cSt) is a hundredth of a stokes, and — notably — centistokes and square millimeter per second share exactly the same factor, 1e-6, because they are in fact the same size unit under two different names.
The featured pair is centistokes to square meter per second: m²/s = cSt × 1e-6, with the reverse direction multiplying by 1,000,000.
A typical SAE 10W motor oil runs around 60 cSt at 40°C, which converts to 60 × 1e-6 = 0.00006 m²/s (6 × 10⁻⁵ m²/s). Water, by comparison, sits near 1 cSt at room temperature, or 1 × 1e-6 = 1 × 10⁻⁶ m²/s.
Kinematic viscosity is the number printed on every lubricant and motor oil data sheet, since SAE and ISO viscosity grades are defined directly in centistokes at a reference temperature. It also drives the Reynolds number used throughout pipeline and pump design to predict whether a flow will be laminar or turbulent, and fuel-injector and nozzle designers use it to size orifices so that fuel atomizes correctly at operating temperature.
The one fact worth remembering here is that centistokes and square millimeter per second are not just similar, they are identical — 1 cSt always equals exactly 1 mm²/s, which is why lubricant manufacturers freely switch between the two labels on the same data sheet. The more consequential mix-up is confusing this page's kinematic viscosity with dynamic viscosity (covered separately): the two differ by a factor of fluid density, so a light oil and a heavy oil with the same dynamic viscosity can show noticeably different centistokes values, and vice versa.
Questions
How many square meter per second are in one centistokes?
One centistokes equals 1 × 10⁻⁶ square meter per second (0.000001 m²/s).
Which units does this kinematic viscosity converter cover?
Seven units referenced to square meter per second: square meter per second, square centimeter per second (stokes), centistokes, square millimeter per second, square foot per second, square inch per second, and square foot per hour.
Why do kinematic viscosity numbers look so small in SI units?
Because the SI unit (m²/s) is defined at a much larger physical scale than the working fluids people usually measure, everyday viscosities land in the 10⁻⁴ to 10⁻⁶ m²/s range; centistokes exists specifically to keep working numbers in a human-friendly range (roughly 1 to a few hundred) instead of writing scientific notation on every data sheet.
When would I use centistokes instead of square meter per second?
Centistokes is the standard on lubricant, motor oil, and hydraulic fluid data sheets because SAE and ISO viscosity grades are defined in cSt at a set reference temperature; square meter per second is used in physics, CFD software, and Reynolds-number calculations where SI-coherent units simplify the surrounding equations.
Are centistokes and square millimeter per second really the same thing?
Yes — 1 cSt equals exactly 1 mm²/s, with no rounding involved, because both are defined as one-millionth of a square meter per second; manufacturers use the two names interchangeably depending on which convention their region or industry prefers.
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