Kinematic Viscosity Converter — Stokes, Centistokes & m²/s
Convert kinematic viscosity between different units including stokes, centistokes, m²/s, mm²/s, ft²/s, and more. Essential for fluid mechanics, lubrication engineering, and hydraulic system design. Kinematic viscosity measures a fluid's resistance to flow under gravity, defined as the ratio of dynamic viscosity to density.
Value:
How to Convert Kinematic Viscosity
- Enter the kinematic viscosity value in the input field above.
- Select the unit you are converting from in the "From" dropdown menu.
- Select the unit you want to convert to in the "To" dropdown menu.
- The result will automatically appear in the result field.
- Use the copy button to copy the result to your clipboard.
- Click any conversion in the list below to quickly select those units.
Kinematic Viscosity Formula
Kinematic Viscosity Definition:
ν = μ/ρ
Where:
ν = Kinematic viscosity (m²/s)
μ = Dynamic (absolute) viscosity (Pa·s)
ρ = Fluid density (kg/m³)
Unit Conversion Formula:
ν₂ = ν₁ × (conversion_factor₁ / conversion_factor₂)
Common Units:
SI Unit: m²/s (square meter per second)
CGS Unit: St (stokes) = cm²/s = 10⁻⁴ m²/s
Common: cSt (centistokes) = mm²/s = 10⁻⁶ m²/s
Imperial: ft²/s, in²/s
Unit Relationships:
1 m²/s = 10⁴ St = 10⁶ cSt
1 St = 100 cSt = 10⁻⁴ m²/s
1 cSt = 1 mm²/s = 10⁻⁶ m²/s
1 ft²/s = 929.0304 St = 92903.04 cSt
1 m²/h = 2.7778 St = 277.78 cSt
Reynolds Number:
Re = vL/ν
Where: v = flow velocity, L = characteristic length
Stokes-Einstein Equation:
D = kT/(6πμr) = kT/(6πρνr)
Where: D = diffusion coefficientExample Conversion
Problem: Convert 32 centistokes (cSt) to stokes (St) and m²/s.
Given: ν = 32 cSt (typical hydraulic oil at 40°C)
Solution:
• To stokes: 32 cSt ÷ 100 = 0.32 St
• To m²/s: 32 cSt × 10⁻⁶ = 3.2×10⁻⁵ m²/s
Answer: 32 cSt = 0.32 St = 3.2×10⁻⁵ m²/s
Technical Details
Kinematic viscosity is the ratio of dynamic viscosity to fluid density, representing a fluid's resistance to flow under gravitational forces. Unlike dynamic viscosity which measures internal friction, kinematic viscosity accounts for the fluid's weight, making it directly measurable with gravity-driven viscometers (capillary tubes). The SI unit is m²/s, but centistokes (cSt) is the most commonly used unit in industry, particularly for lubricant specifications.
In engineering, kinematic viscosity is critical for calculating Reynolds numbers (Re = vL/ν), which determine whether flow is laminar or turbulent. Lubricating oils are typically classified by their kinematic viscosity at 40°C and 100°C (ISO VG grades). Water has a kinematic viscosity of about 1.0 cSt at 20°C, while motor oils range from 5 to 100+ cSt depending on grade and temperature. The viscosity index (VI) measures how much a lubricant's viscosity changes with temperature.
Kinematic Viscosity Reference Table
| Fluid | Viscosity (cSt at 20°C) | Application |
|---|---|---|
| Water | 1.004 | Reference standard fluid |
| Gasoline | 0.6-0.8 | Automotive fuel systems |
| Diesel fuel | 2-5 | Compression ignition engines |
| SAE 10W motor oil (40°C) | 32-46 | Light-duty engine lubrication |
| SAE 30 motor oil (40°C) | 90-110 | Heavy-duty engine lubrication |
| Hydraulic oil ISO VG 32 | 28.8-35.2 | Hydraulic systems at 40°C |
| Honey | 2000-10000 | Food processing reference |
| Air (20°C) | 15.11 (×10⁻⁶ m²/s) | Aerodynamic calculations |
Frequently Asked Questions
What is kinematic viscosity?
Kinematic viscosity is the ratio of a fluid's dynamic viscosity to its density (ν = μ/ρ). It measures how easily a fluid flows under gravity and is expressed in m²/s (SI) or centistokes (cSt). It determines flow behavior in pipes, channels, and around objects.
What is the difference between kinematic and dynamic viscosity?
Dynamic viscosity (μ, in Pa·s or poise) measures internal friction force between fluid layers. Kinematic viscosity (ν, in m²/s or stokes) equals dynamic viscosity divided by density. Kinematic viscosity is what you measure with a gravity-driven capillary viscometer.
Why is centistokes the most common unit?
Centistokes (cSt) gives convenient numbers for most industrial fluids. Water is about 1 cSt, light oils are 10-50 cSt, and heavy oils are 100-1000 cSt. The SI unit m²/s produces very small numbers (10⁻⁶ range) that are less practical for everyday use.
How does temperature affect kinematic viscosity?
For liquids, kinematic viscosity decreases significantly with increasing temperature. Motor oil might be 100 cSt at 40°C but only 10 cSt at 100°C. For gases, kinematic viscosity increases with temperature because density decreases faster than dynamic viscosity increases.
What is the relationship between cSt and mm²/s?
Centistokes and square millimeters per second are exactly the same unit: 1 cSt = 1 mm²/s. This equivalence makes conversion straightforward. Both equal 10⁻⁶ m²/s in SI units.
Objective of Measurement:
Measurement is the most important aspect of our life. We use measurement in science, engineering, business trading, personal life, education, and more other fields. As technology is growing day by day so we need a highly accurate and easy convenient global measuring system in each and every field. It is essential to use standard measurement in every field that everyone to be sure that they not get cheated.
History of Measurement:
In history for measurement people used the human body as a tool. For measuring length used forearm, hand, foot & finger as a unit. The foot, finger is a subdivided shorter unit of a length. This type of measurement is not accurate cause different in size of the arm & finger for different people & some of the countries still using it. In history, there were lots of measuring systems developed but mostly used imperial, the metric system of measurement. We use these systems for measure distances, volume, weight, speed, area etc. Due to this a major problem everyone is facing while doing trading between the countries. A huge improvement in civilization, It necessary to improve measuring standards. Nowadays International Standard (SI) units are used as a global measurement system.
Kinematic Viscosity Calculator - Unit Converter:
Our kinematic viscosity conversion calculator convert square meter/second [m²/s], square meter/hour [m²/h], square centimeter/second [cm²/s], square millimeter/second [mm²/s], square foot/second [ft²/s], square foot/hour [ft²/h], square inch/second [in²/s], stokes [St], exastokes [ESt], petastokes [PSt], terastokes [TSt], gigastokes [GSt], megastokes [MSt], kilostokes [kSt], hectostokes [hSt], dekastokes [daSt], decistokes [dSt], centistokes [cSt], millistokes [mSt], microstokes [µSt], nanostokes [nSt], picostokes [pSt], femtostokes [fSt], attostokes [aSt] vice versa with metric conversion.
Kinematic viscosity conversions & its abbreviations
| Unit | Abbreviation | Unit | Abbreviation |
|---|---|---|---|
| square meter/second | m²/s | square meter/hour | m²/h |
| square centimeter/second | cm²/s | square millimeter/second | mm²/s |
| square foot/second | ft²/s | square foot/hour | ft²/h |
| square inch/second | in²/s | stokes | St |
| centistokes | cSt | kilostokes | kSt |
| millistokes | mSt | microstokes | µSt |
| exastokes | ESt | petastokes | PSt |
| terastokes | TSt | gigastokes | GSt |
| megastokes | MSt | hectostokes | hSt |
| dekastokes | daSt | decistokes | dSt |
| nanostokes | nSt | picostokes | pSt |
| femtostokes | fSt | attostokes | aSt |
Complete list of Kinematic viscosity conversion units and its conversion.
1 square meter/second [m²/s] = 3600 square meter/hour [m²/h]
1 square meter/hour [m²/h] = 0.0002778 square meter/second [m²/s]
1 square centimeter/second [cm²/s] = 100 square millimeter/second [mm²/s]
1 square millimeter/second [mm²/s] = 0.01 square centimeter/second [cm²/s]
1 square foot/hour [ft²/h] = 0.04 square inch/second [in²/s]
1 square inch/second [in²/s] = 25 square foot/hour [ft²/h]
1 stokes [St] = 100 centistokes [cSt]
1 centistokes [cSt] = 0.01 stokes [St]
1 stokes [St] = 0.001 kilostokes [kSt]
1 kilostokes [kSt] = 1000 stokes [St]
1 centistokes [cSt] = 0.00001 kilostokes [kSt]
1 kilostokes [kSt] = 100000 centistokes [cSt]