Chemical Molar Mass & Molecular Formula Calculator

Molar mass (molecular weight) is the sum of atomic weights of all atoms in a chemical formula, expressed in grams per mole.

To use the Chemical Molar Mass & Molecular Formula Calculator, enter your Chemical Formula (e.g. H2O, C6H12O6, NaCl), Sample Mass (for moles calculation). The calculator instantly computes Molar Mass (Molecular Weight), Moles in Sample and more. Results update in real time as you change any input — no submit button needed.

How to Use This Calculator

Enter your Chemical Formula (e.g. H2O, C6H12O6, NaCl) (e.g. H2O) and Sample Mass (for moles calculation) (e.g. 18 in g). Results update instantly as you type — no submit button or page reload required. Adjust any value to compare scenarios side by side.

The Formula

Molar Mass = Sum of (Atomic Weight × Atom Count) for each element

Moles = Mass (g) ÷ Molar Mass (g/mol)

Molecules = Moles × Avogadro's Number (6.022 × 10²³)

Worked Example

Water molecule H₂O, 18g sample:

• Molar Mass: + = 18.015 g/mol.

• Moles in 18g sample: 18 ÷ 18.015 = 0.9992 mol.

• Number of molecules: 0.9992 × 6.022 × 10²³ = 6.016 × 10²³ molecules.

Understanding Your Result

Evaluate your result against the specific financial decision driving this calculation. Small input differences can create large output swings — run two or three scenarios (conservative, base, optimistic) to understand the range of outcomes. For decisions involving more than a month's income, validate your result against a second source or consult a certified financial planner (CFP) or CPA depending on the tax implications.