Free · Physics models
Dry Air Viscosity and Density
Estimate dry-air dynamic viscosity with Sutherland’s law and kinematic viscosity with ideal-gas density.
- Formula & worked example
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Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
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Formula and method
density = 1.1766243 kgm3; dynamic viscosity = 0.000018460015 pascal_seconds; kinematic viscosity = 0.000015688963 sqm_per_second.
μ = 1.458×10⁻⁶ T³ᐟ²/(T+110.4); ρ = p/(RT); ν = μ/ρ.
Worked example
Enter these known values and leave the other values blank.
- Pressure (P)
- 101325 Pa
- Temperature (T)
- 300 K
- Specific gas constant (Rₛ)
- 287.05 J/(kg·K)
- Density (ρ)
- 1.17662 kg/m³
- Dynamic viscosity (μ)
- 0.00001846 Pa⋅s
- Kinematic viscosity (ν)
- 0.000015689 m²/s
Assumptions and limitations
- Estimate dry-air dynamic viscosity with Sutherland’s law and kinematic viscosity with ideal-gas density.
- The retained input domain is 175 K < temperature < 1900 K and 100,000 Pa ≤ pressure ≤ 100,000,000 Pa. The default dry-air gas constant is 287.05 J/(kg·K). This permissive pressure bound does not guarantee ideal-gas accuracy at high pressure.
- Sutherland constants are empirical for air. This model excludes humidity, gas mixtures and nonideal high-pressure behavior; do not treat extrapolation to extreme temperatures as a measured property.
- Inputs and inverse outputs share the displayed unit selectors. Clear a known field to solve for it, and lock quantities that must remain fixed. Singular inverses may have no finite result.
Common questions
Why does pressure affect kinematic viscosity?
Pressure changes the ideal-gas density; kinematic viscosity divides dynamic viscosity by density.
Can I solve dynamic viscosity inversely?
It is a calculated output here. Density, pressure, gas constant and temperature retain their ideal-gas inverse relationship.
References
Estimate dry-air dynamic viscosity with Sutherland’s law and kinematic viscosity with ideal-gas density. Absolute temperature and pressure must be positive. The default dry-air specific gas constant is 287.05 J/(kg·K). Sutherland constants are empirical for air. This model excludes humidity, gas mixtures and nonideal high-pressure behavior; do not treat extrapolation to extreme temperatures as a measured property.