Poise to Stokes Viscosity Converter
Converted Viscosity
Kinematic Viscosity = Dynamic Viscosity / Density. For accurate conversions, ensure the specific gravity or density matches the fluid at its given temperature.What Is a Poise to Stokes Viscosity Converter?
A Poise to Stokes Viscosity Converter calculates the relationship between dynamic viscosity and kinematic viscosity. Dynamic viscosity describes a fluid’s resistance to flow. Kinematic viscosity adjusts that resistance for the fluid’s density. Because the two properties are different, density is required for either conversion direction.
To convert Poise to Stokes, divide dynamic viscosity in Poise by density in grams per cubic centimeter. To convert Stokes to Poise, multiply kinematic viscosity in Stokes by the same density. This calculator normalizes the selected viscosity and density units before applying those formulas.
The tool accepts centiPoise, Poise, Pascal-seconds, milliPascal-seconds, centiStokes, Stokes, square meters per second, and square millimeters per second. Density can be entered as specific gravity, g/cm³, kg/m³, or lb/ft³. Results include a main converted value and three equivalent unit values.
How the Poise to Stokes Conversion Formula Works
For dynamic-to-kinematic conversion, the calculator first changes the entered dynamic viscosity into Poise. It also changes the entered density into grams per cubic centimeter. It then divides the Poise value by the normalized density.
In this formula, ν is kinematic viscosity in Stokes, μ is dynamic viscosity in Poise, and ρ is density in g/cm³.
For the reverse conversion, the calculator changes the entered kinematic viscosity into Stokes. It then multiplies that value by density in g/cm³ to calculate dynamic viscosity in Poise.
Worked example: Enter 100 cP as dynamic viscosity and 1.0 SG as density. The calculator converts 100 cP to 1 P because 1 cP equals 0.01 P. A specific gravity of 1.0 is treated as 1 g/cm³. The calculation is 1 P ÷ 1 g/cm³ = 1 St. This equals 100 cSt and 0.0001 m²/s. Because the original viscosity unit is cP, the main displayed result is 100 cSt.
The calculation accepts zero viscosity, which produces a zero result. Density must be greater than zero because division by zero is not valid. Negative viscosity, negative density, zero density, blank entries, and nonnumeric entries produce an error. The calculator does not estimate density from a fluid name or temperature.
How to Use the Poise to Stokes Viscosity Converter: Step by Step
- Select Dynamic to Kinematic to convert values such as Poise to Stokes. Select Kinematic to Dynamic for the reverse calculation.
- Enter the viscosity value in the Dynamic Viscosity or Kinematic Viscosity field. The field label changes with the selected conversion type.
- Choose the viscosity unit. Dynamic options are cP, P, Pa·s, and mPa·s. Kinematic options are cSt, St, m²/s, and mm²/s.
- Enter the fluid’s density in the Fluid Density field. Use the density that applies to the fluid under the conditions being evaluated.
- Select the density unit from SG, g/cm³, kg/m³, or lb/ft³.
- Select Convert to display the converted viscosity and its equivalent units. Select Reset to restore 100 cP, 1.0 SG, and dynamic-to-kinematic mode.
The main result unit depends on the selected input unit. A cP or mPa·s input produces a main result in cSt. A P or Pa·s input produces St. In reverse mode, cSt or mm²/s produces cP, while St or m²/s produces P. The detail panel always shows three equivalent values.
What to Check Before Converting Viscosity
Use the correct density
Density directly changes the result. For the same dynamic viscosity, a higher density produces a lower kinematic viscosity. For the same kinematic viscosity, a higher density produces a higher dynamic viscosity. The calculator does not provide a built-in list of fluid densities, so the user must supply this value.
Match density to the fluid conditions
Fluid density can change with temperature and pressure. Viscosity can also change greatly with temperature. Use viscosity and density values measured or specified under matching conditions. Mixing values from different temperatures can produce a mathematically valid conversion that does not represent the actual fluid state.
| Input category | Units available in the calculator | Internal base unit |
|---|---|---|
| Dynamic viscosity | cP, P, Pa·s, mPa·s | Poise |
| Kinematic viscosity | cSt, St, m²/s, mm²/s | Stokes |
| Density | SG, g/cm³, kg/m³, lb/ft³ | g/cm³ |
Read small and large values carefully
The calculator normally displays up to four decimal places. Values greater than 99,999 or smaller than 0.0001 are shown in scientific notation. A result such as 1 × 10^-6 represents a very small number, not zero. Zero viscosity is displayed simply as 0.
This converter performs only the unit normalization and density-based viscosity calculation shown in its code. It does not identify fluids, correct values for temperature, assess flow behavior, calculate Reynolds number, or determine whether a fluid is Newtonian. Treat the output as a conversion based on the numbers entered.
Frequently Asked Questions
How do you convert Poise to Stokes?
Divide dynamic viscosity in Poise by fluid density in grams per cubic centimeter. For example, 1 P divided by 1 g/cm³ equals 1 St. The calculator can accept other supported units because it converts them to Poise and g/cm³ before applying the formula.
How do you convert Stokes to Poise?
Multiply kinematic viscosity in Stokes by density in grams per cubic centimeter. A value of 1 St at a density of 1 g/cm³ equals 1 P. The calculator performs this reverse operation when Kinematic to Dynamic is selected as the conversion type.
Is centiPoise the same as centiStokes?
No. CentiPoise measures dynamic viscosity, while centiStokes measures kinematic viscosity. Their numerical values are equal only when the fluid density is 1 g/cm³, or a specific gravity of 1. At other densities, the values differ according to the density-based conversion formula.
Why is density needed to convert viscosity?
Density connects dynamic and kinematic viscosity. Dynamic viscosity measures internal resistance to flow, while kinematic viscosity expresses that resistance relative to density. Without a positive density value, the calculator cannot divide dynamic viscosity correctly or calculate the reverse dynamic viscosity result.
What density units does the converter support?
The converter supports specific gravity, grams per cubic centimeter, kilograms per cubic meter, and pounds per cubic foot. It converts each density input to g/cm³ internally. Specific gravity is treated numerically like density in g/cm³ for the calculation used by this tool.
Can the converter calculate viscosity without density?
No. A positive density value is required for both conversion directions. Blank, nonnumeric, negative, or zero density produces an error. The calculator does not assume a default fluid after the user clears the field, and it does not look up density from a material name.
How accurate is the Poise to Stokes converter?
The calculator follows the coded conversion factors and viscosity formulas for the values entered. Practical accuracy depends on the accuracy of the viscosity and density data. Results may not represent real operating conditions when temperature, pressure, fluid composition, or measurement conditions differ between the entered values.