Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Vapor pressure (hPa)

Required number input.

Total pressure (hPa)

Required number input.

Compute the water vapor mass mixing ratio in grams per kilogram of dry air. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Mixing ratio (g/kg)

The resulting mixing ratio returned as a number.

• Concentration conversions require an unambiguous amount basis, solution volume, density, purity, and temperature. Volumes may not be additive, and molarity, molality, formality, equivalents, and mass fraction are not interchangeable.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Specific Humidity Calculator

  Compute the specific humidity in grams of water vapor per kilogram of moist air.

• Molar Mass From Formula Weight

  Convert a formula weight into an equivalent molar mass in grams per mole.

• Molar Mass From Vapor Density Air Calculator

  Estimate molar mass from vapor density relative to air using M = 28.96 × VD(air).