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Input
Result
Total atoms in the parsed formula: —
| Element | Count | Atomic weight | Partial mass | Mass percent |
|---|
Formula sum
Quantity conversion
Atomic weights are fixed CIAAW 2024 standard values, simplified for display. Results are rounded and intended for education and planning checks.
How the calculation works
The parser expands parentheses, brackets, and hydrate dots before summing each element contribution. The core formula is M = Σ n_i × A_i, where n_i is the atom count and A_i is the atomic weight.
Use this page when the formula is already known. If you need to derive a formula from percent composition or combustion data, use the empirical and molecular formula calculator. If you already know molar mass and need molarity, dilution, or pH, use the concentration and pH calculator.
Input notes
- Hydrates can use an ASCII dot or middle dot, for example CuSO4.5H2O or CuSO4·5H2O.
- State notes and terminal charges such as (aq) and SO4^2- are removed before parsing.
- Isotopes, compound names, SMILES, and custom isotope abundance are out of scope for this version.
FAQ
How do I enter a hydrate such as copper sulfate pentahydrate?
Use a dot before the water coefficient, such as CuSO4.5H2O or CuSO4·5H2O. The calculator expands the hydrate water before summing atomic weights.
Is molar mass the same as molecular weight?
They are often used together in classroom and lab calculations. This page reports molar mass in g/mol from standard atomic weights; molecular weight is the relative mass of the formula unit.
Which atomic weights does this calculator use?
It uses a fixed table of CIAAW 2024 standard atomic weights, simplified to display values. Results are rounded for display.
Why can another molar mass site give a slightly different number?
Small differences usually come from rounded atomic weights, isotope assumptions, or a different atomic-weight table. Compare the element breakdown before comparing only the final total.
Does capitalization matter in a chemical formula?
Yes. Co means cobalt, while CO means carbon monoxide. The calculator does not auto-capitalize formulas because that could change the compound.
Can this calculate isotopes such as D2O or ^13C?
No. This calculator uses standard atomic weights only. Isotope notation such as D, T, or ^13C returns an inline error instead of guessing a mass.
Which elements are available?
The calculator uses CIAAW 2024 standard atomic weights for 84 elements. The 34 elements without a standard atomic weight, including Tc, are unavailable rather than assigned a mass number.
Do display digits change the calculation?
No. Display digits only round shown values. The calculation keeps full available precision and does not round intermediate values.
What does a shared URL contain?
A shared URL contains the formula, quantity, unit, and display digits. Do not put personal information in these fields; opening the URL sends those values as part of the URL.