Kinematic Viscosity Converter

m²/s · cm²/s · mm²/s · St · cSt · ft²/s · in²/s

Convert kinematic viscosity units instantly between m²/s, Stokes (St), centistokes (cSt), ft²/s, and more. Essential for petroleum engineering, hydraulic system design, lubrication, and fluid mechanics.

1 unit =
—
From
Result
—

Quick Reference

  • 1 St = 1 cm²/s = 100 cSt
  • 1 m²/s = 10,000 St
  • Water at 20°C ≈ 1 cSt

Conversion Table

UnitNameValue

About Kinematic Viscosity

Kinematic viscosity (ν) equals dynamic viscosity divided by density: ν = μ/ρ. The SI unit is m²/s, but the centistoke (cSt = mm²/s) is most practical for everyday engineering. Water at 20°C has a kinematic viscosity of about 1 cSt — a useful benchmark.

Unit Systems

The CGS system uses Stokes (St = cm²/s) and centistokes (cSt = mm²/s). The SI system uses m²/s. The imperial system uses ft²/s or in²/s. Most industrial standards (ISO, ASTM) report viscosity in cSt measured at 40°C and 100°C.

Reference Values — Common Fluids

Water (20°C)
≈ 1.004 cSt
Water (50°C)
≈ 0.554 cSt
Diesel fuel
2–5 cSt (40°C)
SAE 30 oil
~100 cSt (40°C)
SAE 10W-40
~95 cSt (40°C)
Glycerin (25°C)
~950 cSt
1 St
= 100 cSt = 1 cm²/s
1 m²/s
= 10,000 St
1 ft²/s
= 929 cm²/s
1 cSt
= 1 mm²/s = 10⁻⁶ m²/s

Worked Examples

1 m²/s to Stokes

1 St = 1 cm²/s = 10⁻⁴ m²/s.
1 m²/s ÷ 10⁻⁴ = 10,000
= 10,000 St

100 cSt to m²/s

1 cSt = 10⁻⁶ m²/s.
100 × 10⁻⁶ = 0.0001
= 1 × 10⁻⁴ m²/s

1 ft²/s to m²/s

1 ft = 0.3048 m, so 1 ft² = 0.0929 m².
1 ft²/s = 0.0929 m²/s
= 0.0929 m²/s

10 St to cSt

1 St = 100 cSt.
10 × 100 = 1,000
= 1,000 cSt

When You Need This Converter

Petroleum Industry

Classify crude oil, fuels, and refined products by viscosity grade using cSt values at standard temperatures.

Hydraulic Systems

Select hydraulic fluids with correct viscosity grades (ISO VG 32, 46, 68) for pumps and actuators.

Chemical Engineering

Calculate Reynolds numbers and friction factors for pipe flow using kinematic viscosity in m²/s.

Food Processing

Measure viscosity of edible oils, syrups, and dairy products to optimize pumping and mixing.

Lubricants

Convert between ISO VG grades and SAE grades, which are defined by kinematic viscosity at 40°C and 100°C.

Automotive

Understand multi-grade engine oil specifications and select correct viscosity for operating temperature ranges.

Mental Math Tips

cSt = mm²/s

Centistokes and mm²/s are the same unit — no conversion needed. Water ≈ 1 cSt = 1 mm²/s at 20°C.

St to cSt

1 St = 100 cSt = 1 cm²/s. Multiply Stokes by 100 to get centistokes. Easy factor of 100.

m²/s to cSt

Multiply m²/s by 1,000,000. So 1 × 10⁻⁶ m²/s = 1 cSt. This is the most common everyday conversion.

You Might Also Need

Dynamic Viscosity Converter Density Converter Flow Rate Converter

Frequently Asked Questions — Kinematic Viscosity Converter

Kinematic viscosity is the ratio of a fluid’s dynamic viscosity to its density (ν = μ/ρ). It measures resistance to flow under gravity. The SI unit is m²/s, though cm²/s (Stokes) and mm²/s (centistokes) are more common in practice.
A centistoke (cSt) equals 1 mm²/s or 10⁻⁶ m²/s. It is the most common unit for lubricating oils, hydraulic fluids, and polymer solutions. Water at 20°C has a kinematic viscosity of approximately 1 cSt — making it a useful reference point.
Dynamic (absolute) viscosity μ measures shear stress per unit shear rate (Pa·s or cP). Kinematic viscosity ν accounts for density: ν = μ ÷ ρ (m²/s). Use kinematic viscosity when fluid density matters, such as in pipe flow and lubrication calculations.
Water’s kinematic viscosity is approximately 1.004 cSt (1.004 mm²/s) at 20°C. It decreases significantly with temperature: about 0.55 cSt at 50°C and 0.29 cSt at 100°C.
SAE grades define kinematic viscosity at 100°C. SAE 30 oil has 9.3–12.5 cSt, SAE 40 has 12.5–16.3 cSt, and SAE 50 has 16.3–21.9 cSt. Multi-grade oils like 10W-40 meet viscosity limits at both low and high temperatures.
Multiply m²/s by 1,000,000 to get cSt. For example, 1 × 10⁻⁶ m²/s = 1 cSt. Conversely, divide cSt by 1,000,000 to get m²/s. This tool handles the conversion automatically.
The Stokes (St) is a CGS unit named after physicist George Gabriel Stokes. 1 St = 1 cm²/s = 100 cSt = 10⁻⁴ m²/s. It’s used in older engineering literature and some petroleum standards. The centistoke (cSt = 0.01 St) is far more common today.

All Kinematic Viscosity Conversions

Common
m²/s → StSt → m²/sm²/s → cStcSt → m²/sSt → cStcSt → St
Full Range
m²/s → cm²/scm²/s → m²/sm²/s → StSt → m²/sSt → cStcSt → Stm²/s → ft²/sft²/s → m²/s