Molar Mass Calculator
Calculate the molar mass of chemical compounds from their formulas. Perfect for chemistry students, teachers, and lab work.
Molar Mass Calculator
Finding the molar mass of a compound doesn't have to be complicated. This Molar Mass Calculator is built to help you get accurate results without the usual confusion that comes with manual calculations.
All you need to do is enter the chemical formula the same way you would write it in your notebook. The calculator recognizes element symbols, subscripts, and parentheses automatically. Once you press calculate, the total molar mass appears instantly.
What makes this tool especially useful is the clear breakdown of each element in the compound. You can see how many atoms are present, their atomic masses, and how each part contributes to the final result. This makes it easier to understand where the number comes from instead of memorizing it.
The clean layout keeps everything focused on the calculation. There are no distracting tables or unnecessary options. If you want a deeper understanding, the step-by-step explanation walks through the process in simple language.
This calculator is ideal for students studying chemistry, teachers explaining concepts in class, and anyone working with chemical formulas in labs or assignments.
With a simple input, clear results, and easy explanations, calculating molar mass becomes straightforward and stress-free.
Enter Chemical Formula
Enter formula normally - subscripts and parentheses are detected automatically
Quick select common compounds or type your own formula above
Calculation Results
Error
Molar Mass
0.00 g/mol
Element Breakdown
| Element | Atomic Mass | Count | Contribution |
|---|
Step-by-Step Calculation
Ready to Calculate?
Enter a chemical formula above to see its molar mass and element breakdown.
How Molar Mass Calculations Work
Molar mass is calculated by adding up the atomic masses of all atoms in a compound. Here's exactly how it works.
Basic Formula
For each element, multiply its atomic mass by the number of atoms, then sum all contributions.
Water Example (H₂O)
Two hydrogen atoms (2 × 1.008) plus one oxygen atom (1 × 16.00) equals the molar mass.
Common Atomic Masses
These values come from the periodic table and represent average atomic masses for naturally occurring isotopes.
What Molar Mass Actually Means
Molar mass connects the microscopic world of atoms to the macroscopic world of grams and moles.
The Mole Connection
One mole of any substance contains 6.022 × 10²³ particles (Avogadro's number). The molar mass tells you the mass of one mole of that substance in grams.
Real-World Mass
Water's molar mass of 18.02 g/mol means one mole of water molecules weighs 18.02 grams. That's about the same as 18.02 mL of water (since 1 mL water = 1 g).
This bridge between atoms and measurable quantities is fundamental to chemistry calculations, stoichiometry, and lab work.
Where Molar Mass Calculations Are Used
Stoichiometry Problems
Calculate how much product you get from reactants, or how much reactant you need for a desired product amount.
Example: How many grams of CO₂ form when 10g of C reacts with oxygen? First find molar masses, then use mole ratios.
Lab Preparation
Making solutions of specific concentration requires knowing molar masses to calculate how much solute to weigh out.
Lab tip: For a 1M NaCl solution, you need 58.44g of NaCl per liter (NaCl's molar mass).
Practical Tips for Molar Mass Calculations
Parentheses Matter
In Ca(OH)₂, the subscript ₂ applies to everything inside the parentheses. So it's Ca + 2×(O + H), not Ca + O + 2×H.
Case Sensitivity
Element symbols are case-sensitive. 'Co' is cobalt, 'CO' is carbon monoxide. The calculator handles this automatically.
Round Appropriately
Atomic masses have different precision. Use the same number of decimal places as your least precise atomic mass.
Common Mistake to Avoid
Don't forget that molar mass is always in g/mol. If you're working in mg/mmol or other units, convert accordingly.
Molar Mass Questions People Actually Ask
What's the difference between molecular weight and molar mass?
They're essentially the same thing. "Molecular weight" is an older term, but "molar mass" is more accurate since it applies to compounds that aren't molecules (like ionic compounds).
Why do atomic masses have decimal points?
Elements exist as mixtures of isotopes with different masses. The atomic mass is a weighted average. For example, chlorine is 75.8% ³⁵Cl and 24.2% ³⁷Cl, giving an average of 35.45.
How do I calculate molar mass for hydrates?
Include the water molecules. For CuSO₄·5H₂O, calculate CuSO₄ first, then add 5 × H₂O. The dot indicates "associated with" but not chemically bonded.
What if my compound has a polyatomic ion?
Treat polyatomic ions as units. For example, in Ca(NO₃)₂, there are two NO₃ groups. Calculate NO₃ as N + 3×O = 62.00, then Ca + 2×NO₃.