Molar Mass Calculator

How do I calculate molar mass?

How to use

  1. Enter your values in the fields above.
  2. Press Calculate to see your result instantly.
  3. Use the Share button to copy a link to your result.

About this calculator

This tool calculates the molar mass of a chemical compound — the mass in grams of one mole (6.022×10²³ particles) of that substance — by parsing a formula like H2O or CaCO3, looking up the atomic weight of each element involved, and summing them according to how many atoms of each appear. Getting this number right depends on correctly reading subscripts and parentheses in the formula, which is where manual calculation most often goes wrong.

It is used by chemistry students working through stoichiometry homework, and by lab technicians and researchers who need to convert between a target mass and a target number of moles when preparing a solution of a specific concentration. Molar mass is also the starting point for calculating things like molarity, percent composition and reaction yields, so it's typically the first number worked out in any quantitative chemistry problem.

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