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Ideal Gas Law Calculator

Solve the ideal gas equation PV = nRT for whichever variable you need — pressure, volume, temperature, or moles — given the other three. The foundational equation for any gas-phase chemistry or thermodynamics problem at moderate temperatures and pressures.

Pressure (P) (atm)

Volume (V) (L)

Temperature (T) (K)

Gas Constant (R)

Solve For

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Chemistry

Molecular Weight Calculator

Compute the molecular weight (molar mass, g/mol) of a CHON-containing molecule from the number of carbon, hydrogen, oxygen, and nitrogen atoms in its formula, with an optional isotope-correction factor. Useful for routine stoichiometry on organic and biological molecules where C, H, O, and N dominate the elemental composition.

Carbon Atoms (C) (atoms)

Hydrogen Atoms (H) (atoms)

Oxygen Atoms (O) (atoms)

Nitrogen Atoms (N) (atoms)

Isotope Correction

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Key differences

	Ideal Gas Law Calculator	Molecular Weight Calculator
Category	Chemistry	Chemistry
Inputs required	5	5
Result	Calculated Value (varies)	Molecular Weight (g/mol)
What it does	Solve the ideal gas equation PV = nRT for whichever variable you need — pressure, volume, temperature, or moles — given the other three. The foundational equation for any gas-phase chemistry or thermodynamics problem at moderate temperatures and pressures.	Compute the molecular weight (molar mass, g/mol) of a CHON-containing molecule from the number of carbon, hydrogen, oxygen, and nitrogen atoms in its formula, with an optional isotope-correction factor. Useful for routine stoichiometry on organic and biological molecules where C, H, O, and N dominate the elemental composition.