The density converter changes mass-density units. The viscosity converter changes dynamic-viscosity units. They accept a known number and its unit; neither measures a material or computes one property from the other.
| Feature | Density | Dynamic viscosity |
|---|---|---|
| Controls | Value, From unit, To unit | Value, From unit, To unit |
| Supported units | kg/m³, g/cm³, lb/ft³ | Pa·s, P, cP, mPa·s |
| Conversion base | kg/m³ | Pa·s |
| Primary/detail format | Fixed 6 fractional places | Pa·s fixed 6; P, cP and mPa·s fixed 4 |
| Supporting panel | All 3 supported density units | All 4 supported viscosity units |
For density, 1 g/cm³ = 1,000 kg/m³. The lb/ft³ bridge is derived from the defined pound and international foot: 0.45359237 ÷ 0.3048³ kg/m³ per lb/ft³. A finite decimal approximation of this ratio is not a separate exact definition. With 0.8 g/cm³ → lb/ft³, the displayed result is 49.942368 lb/ft³.
For dynamic viscosity, 1 P = 0.1 Pa·s and 1 cP = 1 mPa·s = 0.001 Pa·s. Entering 0.75 Pa·s → cP displays 750.0000 cP. The density default 1,000 kg/m³ → g/cm³ displays 1.000000 g/cm³; viscosity defaults to 1 Pa·s → 1,000.0000 cP.
Both forms retain the entered value’s conversion before formatting and copy the target result at the same fixed fractional-place count as their primary display. There is no precision selector. Fixed digits are a presentation choice, not a statement of measurement uncertainty.
These are separate unit conversions. The controls contain no temperature, pressure, shear-rate, material test or combined density/viscosity input. This comparison makes no temperature-standard, constitutive-law or kinematic-viscosity conversion claim. Select the converter matching the quantity and unit you already have.
Sources
- NIST SP 811, 2008 edition — Exact pound and international foot definitions for density-unit derivation; 1 poise = 0.1 Pa·s and SI decimal prefixes for dynamic-viscosity units. No temperature or rheology-method claim.