square millimetres per second (mm2/s) to square metres per second (m2/s) conversion

1 mm2/s = 0.000001 m2/sm2/s → mm2/s
Formula
1 mm2/s = 0.000001 m2/s

Understanding Square Millimetres Per Second to Square Metres Per Second Conversion

The square millimetre per second (mm²/s) is a practical metric unit of kinematic viscosity — identical to the centistokes — while the square metre per second (m²/s) is the coherent SI unit. Since a metre is a thousand millimetres, their areas differ by a factor of a million. This conversion is used to feed everyday lubricant and fuel viscosities into SI-based calculations, simulations, and dimensional analysis.

Conversion Formula

1 mm2/s=1.00000×10−6 m2/s1\ \text{mm2/s} = 1.00000 \times 10⁻⁶\ \text{m2/s}

To convert square millimetres per second to square metres per second, multiply by this factor:

m2/s=mm2/s×0.000001\text{m2/s} = \text{mm2/s} \times 0.000001

Step-by-Step Example

Convert 25 square millimetres per second to square metres per second.

m2/s=25×0.000001=0.000025 m2/s\text{m2/s} = 25 \times 0.000001 = 0.000025\ \text{m2/s}

How to Convert Square Millimetres Per Second to Square Metres Per Second

Follow these steps to bring a practical viscosity value into coherent SI units.

  1. Know the factor: One square millimetre per second equals 0.000001 square metres per second.
  2. Take your value: Record the kinematic viscosity in mm²/s (equivalently centistokes).
  3. Multiply: Multiply by 1 × 10⁻⁶ to obtain m²/s.
  4. Worked result: For 25 mm²/s, 25 × 0.000001 = 0.000025 m²/s.

square millimetres per second to square metres per second conversion table

square millimetres per second (mm2/s)square metres per second (m2/s)
00
10.000001
20.000002
30.000003
40.000004
50.000005
60.000006
70.000007
80.000008
90.000009
100.00001
150.000015
200.00002
250.000025
300.00003
400.00004
500.00005
600.00006
700.00007
800.00008
900.00009
1000.0001
1500.00015
2000.0002
2500.00025
3000.0003
4000.0004
5000.0005
6000.0006
7000.0007
8000.0008
9000.0009
10000.001
20000.002
30000.003
40000.004
50000.005
100000.01
250000.025
500000.05
1000000.1
2500000.25
5000000.5
10000001

What is the square millimetre per second?

The square millimetre per second (mm²/s) is the practical SI unit of kinematic viscosity, numerically identical to the centistokes (cSt). It is the unit in which most liquid viscosities are quoted in engineering and lubrication data sheets.

Definition

One square millimetre per second is one millionth of a square metre per second:

1 mm2/s=0.000001 m2/s1\ \text{mm}^2/\text{s} = 0.000001\ \text{m}^2/\text{s}

Because 1 mm=10−3 m1\ \text{mm} = 10⁻³\ \text{m}, area scales as 10−610⁻⁶, so 1 mm2/s=10−6 m2/s1\ \text{mm}^2/\text{s} = 10⁻⁶\ \text{m}^2/\text{s}. It is exactly equal to one centistokes: 1 mm2/s=1 cSt1\ \text{mm}^2/\text{s} = 1\ \text{cSt}.

Origin and History

As the SI displaced the CGS system, the centistokes was re-expressed in coherent SI form as mm²/s, keeping the numerical values in existing tables unchanged. This convenient one-to-one equality made the transition seamless for industries such as petroleum and lubricants that had decades of data in centistokes.

Law and Notable Facts

It is a coherent submultiple within SI usage and the de facto standard for viscosity grades. ISO viscosity grade (VG) numbers, such as ISO VG 46, are defined by the fluid's mid-point kinematic viscosity in mm²/s at 40 °C — so ISO VG 46 oil is nominally 46 mm²/s at 40 °C.

Real-World Examples and Conversions

Water at 20 °C is about 1.004 mm²/s (1.004 cSt). Typical engine oil at 100 °C ranges from roughly 5 to 21 mm²/s depending on SAE grade. One mm2/s\text{mm}^2/\text{s} equals 10−6 m2/s10⁻⁶\ \text{m}^2/\text{s} and 10−2 stokes10⁻²\ \text{stokes}.

What is the square metre per second?

The square metre per second (m²/s) is the SI derived unit of kinematic viscosity and of diffusivity. Kinematic viscosity is the ratio of a fluid's dynamic viscosity to its density, describing how readily a fluid flows under gravity independent of its mass.

Definition

One square metre per second is the SI coherent unit of kinematic viscosity, obtained by dividing dynamic viscosity (Pa·s) by density (kg/m³):

1 m2/s=1 m2/s1\ \text{m}^2/\text{s} = 1\ \text{m}^2/\text{s}

Equivalently, 1 m2/s=1 Pa·s÷1 kg/m31\ \text{m}^2/\text{s} = 1\ \text{Pa·s} \div 1\ \text{kg/m}^3. Its dimensions are area per time (L²T⁻¹). The same unit measures mass diffusivity and thermal diffusivity.

Origin and History

The concept of kinematic viscosity was developed in fluid mechanics to separate a fluid's resistance to shear (dynamic viscosity) from the inertial effect of its density. The SI adopted the coherent unit m²/s as part of the metre-kilogram-second framework, replacing the older CGS stokes (cm²/s).

Law and Notable Facts

The m²/s is the SI-preferred unit, but it is inconveniently large for most liquids, so the millimetre-squared per second (mm²/s), equal to the centistokes, dominates practical tabulation. The Reynolds number, Re=vL/νRe = vL/\nu, uses kinematic viscosity ν\nu directly in m²/s.

Real-World Examples and Conversions

Water at 20 °C has a kinematic viscosity of about 1.004×10−6 m2/s1.004\times10^{-6}\ \text{m}^2/\text{s} (1.004 cSt). Air at 20 °C is roughly 1.5×10−5 m2/s1.5\times10^{-5}\ \text{m}^2/\text{s}, higher than water because of air's low density. One m2/s\text{m}^2/\text{s} equals 10,000 stokes10{,}000\ \text{stokes} or 106 mm2/s10⁶\ \text{mm}^2/\text{s}.

Frequently Asked Questions

How many square metres per second are in one square millimetre per second?

One square millimetre per second equals 0.000001 square metres per second, since a square metre contains a million square millimetres.

What is the multiplication factor?

Multiply the mm²/s value by 1 × 10⁻⁶. For example, 320 mm²/s equals 0.00032 m²/s.

Why convert practical viscosities to m²/s?

SI-based engineering formulas, Reynolds-number calculations, and CFD tools expect kinematic viscosity in m²/s, so datasheet values in mm²/s must be scaled down first.

Is mm²/s the same as centistokes here?

Yes, one square millimetre per second equals one centistokes, so this conversion also turns centistokes into SI m²/s.

How do I convert back to mm²/s?

Multiply the m²/s value by 1,000,000, so 0.000025 m²/s returns to 25 mm²/s.

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Complete square millimetres per second conversion table

mm2/s
UnitResult
square metres per second (m2/s)0.000001 m2/s
stokes (St)0.01 St
centistokes (cSt)1 cSt
square feet per second (ft2/s)0.00001076391 ft2/s

Kinematic viscosity conversions