Molar Mass Calculator
Chemical formula → molecular weight with element breakdown
Formula
Supports parentheses: Ca(OH)2, K4[Fe(CN)6] style nesting (use ( ) only).
g/mol
| Element | Atoms | Atomic mass | Total |
|---|---|---|---|
Molar Mass Calculator — Complete Guide & Instructions
MakeCard Molar Mass Calculator turns any chemical formula into its molecular weight in grams per mole, complete with a per-element breakdown. Type a formula such as H2SO4, Ca(OH)2 or even a nested hydrate like K4[Fe(CN)6]-style groupings with round brackets and the parser counts every atom, multiplies by standard atomic masses and totals the result. It is built for chemistry students checking homework, lab staff preparing molar solutions, and teachers generating worked examples.
How to Use Molar Mass Calculator
- 1 Type the chemical formula into the "Formula" box using normal notation — e.g. H2SO4, NaCl or Ca(OH)2.
- 2 Use round brackets for grouped atoms: Ca(OH)2 means two OH groups; brackets can be nested for complex compounds.
- 3 Click "Calculate" or press Enter on the keyboard.
- 4 Read the total molar mass shown in g/mol at the top of the result card.
- 5 Check the breakdown table for each element's atom count, atomic mass and contribution to the total.
Key Features & Capabilities
- Parses plain chemical notation — element symbols followed by atom counts, exactly as written in textbooks.
- Supports round-bracket grouping and nested parentheses for polyatomic ions and complex salts.
- Per-element breakdown table shows atom count, atomic mass and mass contribution side by side.
- Covers 49 common elements from hydrogen to lead — the set used in school, college and lab chemistry.
- Clear error messages pinpoint unknown symbols or unclosed brackets so mistakes are easy to fix.
- Runs instantly in the browser with no waiting, loading or page reload.
Supported Formats & Specifications
| Parameter | Specification |
|---|---|
| Input Format | Standard formula notation — symbols + counts, round brackets for groups (nesting supported) |
| Element Database | 49 elements (H through Pb) with standard atomic masses |
| Output | Total molar mass in g/mol (4 decimals) + element breakdown table |
| Grouping Syntax | Round brackets ( ) only — square and curly brackets are not parsed |
| Access Mode | Free browser tool, no account or download required |
Practical Everyday Use Cases
- Chemistry homework — verify the molar mass of compounds before stoichiometry or mole-conversion problems.
- Preparing molar solutions in the lab: convert "weigh X grams per litre" instructions into exact masses.
- Checking hydrate and complex formulas with brackets, like CuSO4·5H2O-style groupings written as nested groups.
- Teachers building answer keys and worked examples for class worksheets.
- Quick sanity checks when balancing reactions or calculating percentage composition.
Pro Tips for Best Results
- Element symbols are case-sensitive — write "Co" for cobalt, not "CO" (which reads as carbon + oxygen).
- Only round brackets group atoms; formulas like Fe2(SO4)3 work, but rewrite [Fe(CN)6] with ( ) instead.
- For hydrates like CuSO4·5H2O, replace the dot with a plus-free sum — compute CuSO4 and 5×H2O separately and add them.
- Double-check the atom-count table when a result looks off — a missed subscript is the most common error.
Common Problems & Solutions
The built-in table covers 49 common elements. Rare earths, actinides and synthetic elements are not included — compute those manually or split the formula.
Only round brackets are supported and every ( needs a matching ). Square-bracket notation must be rewritten as round brackets before calculating.
"Mg" and "MG" are different — always capitalise the first letter of each symbol and lowercase the second.
Privacy & Security
100% Client-Side Execution
Formula calculations run entirely in your browser — nothing you type is sent to or stored on a server.
Frequently Asked Questions
Everything you need to know about using Molar Mass Calculator
Enter the formula exactly as written — for example H2SO4 — and click Calculate. The tool counts each atom, multiplies by the element's atomic mass and shows the total in g/mol with a breakdown.
H2O has 2 hydrogen atoms (2 × 1.008) plus 1 oxygen (15.999), giving a molar mass of about 18.015 g/mol. Type it into the calculator to see the full breakdown.
Yes — round brackets work for groups like Ca(OH)2 or Fe2(SO4)3, and brackets can be nested. Square and curly brackets are not recognised.
Atomic mass is the mass of one atom of an element in atomic mass units; molar mass is the mass of one mole of a substance expressed in g/mol — the same number, different unit and scale.
The element table covers the 49 most common elements. Symbols for heavier or rare elements (like U or La) are not included, and lowercase-only spellings like "mg" will also fail.
Related FreeToolsBazaar Tools
Ready to Use Molar Mass Calculator?
100% free, browser-based, and private. No installation, registration, or file upload to external servers required.
Start Using Molar Mass Calculator