🌀 Kinematic Viscosity Converter 2026
Convert between stokes, centistokes, m²/s, and other kinematic viscosity units
1 St = 100 cSt
Formula: value × 100
📊 All Conversions
Common Viscosity Conversions
| From | To | Multiply by |
|---|---|---|
| 1 stokes (St) | centistokes (cSt) | 100 |
| 1 centistokes (cSt) | m²/s | 10⁻⁶ |
| 1 stokes (St) | m²/s | 10⁻⁴ |
| 1 m²/s | stokes | 10,000 |
| 1 ft²/s | m²/s | 0.0929 |
| 1 m²/s | ft²/s | 10.764 |
Typical Kinematic Viscosities (at 40°C)
| Fluid | Kinematic Viscosity |
|---|---|
| 💧 Water (20°C) | 1.004 cSt |
| 🛢️ SAE 10W motor oil | 32–40 cSt |
| 🛢️ SAE 30 motor oil | 100–110 cSt |
| 🛢️ SAE 40 motor oil | 130–150 cSt |
| ⚙️ ISO VG 32 hydraulic oil | 28.8–35.2 cSt |
| ⚙️ ISO VG 68 hydraulic oil | 61.2–74.8 cSt |
| 🧴 Olive oil (25°C) | ~84 cSt |
| 🌫️ Air (20°C) | 15.1 cSt |
Understanding Kinematic Viscosity
🌀 Stokes (St)
CGS unit. 1 St = 1 cm²/s = 10⁻⁴ m²/s. Named after George Stokes. Centistokes (cSt) more common: 1 cSt = 0.01 St.
📐 m²/s
SI unit. 1 m²/s = 10,000 St = 10⁶ cSt. Very large for most fluids. Water ≈ 10⁻⁶ m²/s = 1 cSt.
⚖️ Kinematic vs Dynamic
Kinematic ν = μ/ρ. Dynamic viscosity (μ) divided by density (ρ). "How fast a fluid flows under gravity."
🌡️ Temperature Effect
Viscosity changes with temperature. ISO VG grades measured at 40°C. Oil viscosity drops significantly when hot.
Frequently Asked Questions
What is kinematic viscosity?
Kinematic viscosity (ν) is dynamic viscosity divided by fluid
density. It describes how a fluid flows under gravity. Used for lubricant grading. Unit: m²/s or stokes
(St).
How do I convert stokes to centistokes?
Multiply by 100. 1 St = 100 cSt. Centistokes is more practical for
most fluids. Water ≈ 1 cSt.
How do I convert centistokes to m²/s?
Multiply by 10⁻⁶. 1 cSt = 10⁻⁶ m²/s = 1 mm²/s. Example: 100 cSt =
10⁻⁴ m²/s.
What is a centistoke?
1/100 of a stokes. 1 cSt = 0.01 St = 1 mm²/s = 10⁻⁶ m²/s. Most
common unit for oil viscosity. Water ≈ 1 cSt at 20°C.
What is the kinematic viscosity of water?
~1.004 cSt at 20°C. Varies with temperature: 1.79 cSt at 0°C, 0.66
cSt at 40°C, 0.29 cSt at 100°C.
What is the difference between kinematic and dynamic viscosity?
Kinematic ν = μ/ρ. Dynamic (μ) in Pa·s; kinematic (ν) in m²/s.
Kinematic accounts for density. Same dynamic viscosity + lower density = higher kinematic viscosity.
What does cSt mean in oil?
Centistokes. Standard unit for lubricant viscosity. ISO VG
(Viscosity Grade) number equals cSt at 40°C. SAE grades based on cSt at 100°C.
How do I convert kinematic to dynamic viscosity?
Multiply by density: μ = ν × ρ. If ν is in cSt and ρ in g/cm³,
result is in centipoise (cP). For water (ρ≈1): cSt ≈ cP.
What is ISO VG rating?
ISO Viscosity Grade. Number equals midpoint kinematic viscosity in
cSt at 40°C. ISO VG 32 = 28.8-35.2 cSt. ISO VG 100 = 90-110 cSt.
What is SAE viscosity grade?
Society of Automotive Engineers oil classification. Based on
viscosity at 100°C (and low-temp for "W" grades). SAE 30 ≈ 9.3-12.5 cSt at 100°C.
What is a stokes named after?
Sir George Gabriel Stokes (1819-1903), Irish physicist. Stokes'
law describes settling of spheres in viscous fluids. Also worked on fluid dynamics and optics.
Why is kinematic viscosity important for lubricants?
Determines flow and film formation. Too thin: poor lubrication,
wear. Too thick: drag, poor cold starts. Must match application temperature range.
What is viscosity index (VI)?
Measures viscosity change with temperature. Higher VI = more
stable viscosity. Modern oils: VI 80-150+. Multi-grade oils have higher VI than monograde.
How does temperature affect kinematic viscosity?
Decreases as temperature increases (for liquids). Motor oil: ~100
cSt at 40°C → ~15 cSt at 100°C. This is why VI matters.
What is mm²/s vs cSt?
They are equal! 1 cSt = 1 mm²/s exactly. mm²/s is SI-compatible
notation for centistokes. Both widely used.
What is the kinematic viscosity of air?
~15.1 cSt at 20°C. Higher than water! Air has low dynamic
viscosity but also low density. Kinematic = dynamic/density.
How accurate is this kinematic viscosity converter?
Uses exact conversion factors. Results are mathematically precise.
Actual fluid viscosity varies with temperature, pressure, shear rate.