Convert kinematic viscosity units — m²/s, Stokes, centistokes, ft²/s and more.
| Unit | Name | Value |
|---|---|---|
| m²/s | Square Meter/Second | 0.00064516 |
| cm²/s | Square Centimeter/Second | 6.4516 |
| St | Stokes | 6.4516 |
| cSt | Centistokes | 645.16 |
| ft²/s | Square Foot/Second | 0.0069444474 |
Formula: ft²/s = in²/s × 0.006944
Multiply any in²/s value by 0.006944 to get ft²/s.
Reverse: in²/s = ft²/s × 144
Water reference (20°C): 0.001556 in²/s = 1.0807e-5 ft²/s
Values at ~20°C unless noted. Factor: 1 in²/s = 0.006944 ft²/s
| in²/s (in²/s) | ft²/s (ft²/s) | Fluid |
|---|---|---|
| 2.325e-05 in²/s | 1.615e-07 ft²/s | Air (20°C) |
| 0.000775 in²/s | 5.382e-06 ft²/s | Petrol (gasoline) |
| 0.001556 in²/s | 1.081e-05 ft²/s | Water (20°C) |
| 0.002325 in²/s | 1.615e-05 ft²/s | Ethanol |
| 0.00465 in²/s | 3.229e-05 ft²/s | Diesel fuel |
| 0.05425 in²/s | 0.0003767 ft²/s | SAE 10W motor oil |
| 0.1302 in²/s | 0.0009042 ft²/s | Olive oil |
| 0.155 in²/s | 0.001076 ft²/s | SAE 30 motor oil |
| 0.279 in²/s | 0.001938 ft²/s | SAE 90 gear oil |
| 2.186 in²/s | 0.01518 ft²/s | Glycerin (20°C) |
| 7.75 in²/s | 0.05382 ft²/s | Honey |
| 12.4 in²/s | 0.08611 ft²/s | Molasses |
| 77.5 in²/s | 0.5382 ft²/s | Tomato ketchup |
| 387.5 in²/s | 2.691 ft²/s | Peanut butter |
| 1.550e+18 in²/s | 1.076e+16 ft²/s | Glass (room temp) |
1 in²/s = 0.006944 ft²/s.
Water at 20°C = 1 cSt = 0.01 St = 10⁻⁶ m²/s. Use as reference.
Multiply result by 144 to recover the original in²/s value.
Specifies lubricant viscosity grades in cSt at 40°C and 100°C per ISO VG and SAE standards.
Uses kinematic viscosity in cSt for pipeline flow calculations, pump sizing, and heat exchanger design.
Measures crude oil and refined product viscosity in cSt for pipeline transport and refinery design.
Selects hydraulic fluids based on kinematic viscosity in cSt for pump compatibility and system efficiency.
Characterizes food product viscosity (honey, sauces, oils) in cSt for process design and quality control.
Uses ft²/s or cSt for atmospheric kinematic viscosity in Reynolds number calculations for aircraft design.
Square inch per second (in²/s) is occasionally used in US precision engineering and hydraulic system specifications where inch-based units are standard. One in²/s = 6.4516×10⁻⁴ m²/s = 6.4516 St.
In²/s appears in some US hydraulic fluid specifications and industrial machinery manuals. A typical hydraulic fluid at 40°C might be specified as 0.04 in²/s (40 cSt). It is rarely used in modern practice compared to cSt.
Interesting fact: Hydraulic systems in US aircraft were historically specified using in²/s for fluid viscosity, alongside psi for pressure and gpm for flow — a fully inch-pound unit system that required separate conversion when integrating with metric components.
Square foot per second (ft²/s) is the Imperial kinematic viscosity unit, equal to 0.0929 m²/s = 929 St. It is used in US aerospace and some civil engineering contexts where the foot-pound-second system is standard.
ft²/s appears in some US military fluid specifications and older aerospace engineering handbooks. Water at 20°C ≈ 1.075×10⁻⁵ ft²/s. Air ≈ 1.57×10⁻⁴ ft²/s. The large scaling factor (1 ft²/s = 929 St) makes it impractical for most engineering use.
Interesting fact: The kinematic viscosity of the atmosphere at different altitudes is important for aircraft design — Reynolds number calculations use kinematic viscosity. The US Standard Atmosphere tables list kinematic viscosity in ft²/s at each altitude for use in US aerospace engineering.
Kinematic viscosity (ν = μ/ρ) measures how a fluid flows under gravity. The cSt is dominant in industry; m²/s is the SI unit; St and cm²/s are the CGS equivalents. Key anchor: water at 20°C ≈ 1 cSt = 10⁻⁶ m²/s = 0.01 St.
Exact factor: 1 in²/s = 0.006944 ft²/s. Reverse: 1 ft²/s = 144 in²/s.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.