Molar Mass Calculator
Calculate the molar mass (molecular weight) of any chemical formula with element-by-element mass composition. Supports brackets and hydrates.
How to use the Molar Mass Calculator
- Enter or select: Chemical formula.
- Fill in what you know of: Sample mass (optional) — leave the unknown empty.
- The results (Molar mass, Formula, Amount in sample, Composition by mass) are calculated instantly as you type.
- Use “Copy link” to share the calculation with the same input values.
Formula
- M = Σ nᵢ · Aᵣ(i)
About this tool
Write formulas with normal digits: H2SO4, Ca(OH)2, K4[Fe(CN)6]. Use . or · for hydrates: CuSO4.5H2O. Element symbols are case sensitive (Co ≠ CO).