# Viscosity Kinematic Converter

> Convert between kinematic viscosity units: square meter per second (m²/s), stokes, centistokes, square foot per second, and more.

**Category:** Conversion
**Keywords:** viscosity, kinematic, stokes, centistokes, cSt, St, m²/s, square meter per second, square foot per second, fluid, oil, convert
**URL:** https://complete.tools/viscosity-kinematic-converter

## How it calculates

**Formula:**
```
result = inputValue × (fromUnitFactor / toUnitFactor)
```

**Where:**
- **inputValue** = the kinematic viscosity value in the source unit
- **fromUnitFactor** = conversion factor from source unit to m²/s
- **toUnitFactor** = conversion factor from target unit to m²/s

**Conversion factors to m²/s (SI base unit):**
- **m²/s** = 1 (SI base unit)
- **Stokes (St)** = 0.0001 m²/s (equivalent to 1 cm²/s)
- **Centistokes (cSt)** = 0.000001 m²/s (1/100 of a Stokes)
- **cm²/s** = 0.0001 m²/s (same as Stokes)
- **ft²/s** = 0.09290304 m²/s
- **in²/s** = 0.00064516 m²/s

**Note:** Kinematic viscosity (ν) = Dynamic viscosity (μ) / Density (ρ)

## Who should use this

- **Lubrication engineers** selecting and specifying oils and greases for machinery based on viscosity requirements
- **Oil analysts** interpreting used oil analysis reports that typically report kinematic viscosity in centistokes
- **HVAC technicians** working with refrigerant oils and compressor lubricants
- **Automotive technicians** comparing motor oil viscosity grades and specifications
- **Fluid engineers** designing hydraulic systems, pipelines, and pumping equipment
- **Chemical engineers** calculating fluid flow characteristics in process equipment
- **Quality control technicians** testing lubricant and fuel samples against specifications

## Applications

**Oil Analysis:**
Used oil analysis programs measure kinematic viscosity (typically in cSt at 40°C and 100°C) to detect contamination, oxidation, or wrong oil usage. A viscosity change of more than 10-15% often indicates a problem requiring investigation.

**Fluid Engineering:**
Kinematic viscosity directly affects Reynolds number calculations, which determine whether flow is laminar or turbulent. This is critical for pipe sizing, pump selection, and heat exchanger design.

**HVAC Systems:**
Refrigeration compressors require specific oil viscosities for proper lubrication. The oil must flow at low temperatures during startup while maintaining adequate film thickness at operating temperatures.

**Lubricant Selection:**
Motor oil viscosity grades (like SAE 5W-30) are based on kinematic viscosity measurements. The first number (5W) relates to cold-start viscosity, while the second (30) indicates viscosity at 100°C.

## Worked examples

**Example 1: Converting motor oil viscosity**
A motor oil has a kinematic viscosity of 100 cSt at 40°C. Convert to m²/s.
- Calculation: 100 cSt × 0.000001 = 0.0001 m²/s
- Result: 100 cSt = 0.0001 m²/s = 1 Stokes

**Example 2: Converting from imperial units**
A technical specification lists viscosity as 0.001 ft²/s. Convert to centistokes.
- First convert to m²/s: 0.001 × 0.09290304 = 0.00009290304 m²/s
- Then convert to cSt: 0.00009290304 / 0.000001 = 92.90304 cSt
- Result: 0.001 ft²/s = 92.9 cSt

**Example 3: Comparing fluid viscosities**
Water has a kinematic viscosity of about 1 cSt at 20°C. SAE 30 motor oil is approximately 100 cSt at 40°C.
- Water in Stokes: 1 cSt = 0.01 St
- SAE 30 oil in Stokes: 100 cSt = 1.0 St
- The oil is 100 times more viscous than water

## Unit definitions

**Square meter per second (m²/s):**
The SI unit of kinematic viscosity. One m²/s equals 10,000 Stokes, making it a very large unit rarely used for practical measurements.

**Stokes (St):**
Named after George Stokes, defined as 1 cm²/s. Commonly used in the CGS system but largely replaced by centistokes for practical applications.

**Centistokes (cSt):**
One hundredth of a Stokes (0.01 St). The most common unit in oil analysis and lubricant specifications. Water at 20°C has a viscosity of approximately 1 cSt.

**Square centimeter per second (cm²/s):**
Equivalent to Stokes. Used in scientific literature following CGS conventions.

**Square foot per second (ft²/s):**
Imperial unit occasionally found in older American engineering references and some industrial specifications.

**Square inch per second (in²/s):**
Less common imperial unit, sometimes used in specialized applications.

## Limitations

- Kinematic viscosity varies significantly with temperature; this tool does not perform temperature corrections
- The tool assumes Newtonian fluid behavior; non-Newtonian fluids (like grease or polymer solutions) may require different measurement approaches
- Very high precision applications may require consideration of significant figures beyond what this calculator displays
- The tool does not convert between kinematic and dynamic viscosity (which requires knowing the fluid density)

## FAQs

**
**Q:** What is the difference between kinematic and dynamic viscosity?**


**A:** Dynamic viscosity (μ) measures internal resistance to flow. Kinematic viscosity (ν) is dynamic viscosity divided by density (ν = μ/ρ). Kinematic viscosity accounts for the fluid's weight, which affects flow under gravity.

**
**Q:** Why do oil specifications use centistokes?**


**A:** Centistokes provide convenient numbers for common fluids. Water is about 1 cSt, light oils are 10-50 cSt, and heavy oils are 100-1000 cSt. Using m²/s would result in very small, awkward numbers.

**
**Q:** At what temperature should viscosity be measured?**


**A:** Standard temperatures are 40°C (104°F) for industrial oils and 100°C (212°F) for engine oils. Always note the temperature when reporting viscosity values.

**
**Q:** How do I convert if I only have dynamic viscosity?**


**A:** Divide dynamic viscosity by density. For example, if dynamic viscosity is 0.001 Pa·s and density is 1000 kg/m³, kinematic viscosity = 0.001/1000 = 0.000001 m²/s = 1 cSt.

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*Generated from [complete.tools/viscosity-kinematic-converter](https://complete.tools/viscosity-kinematic-converter)*