Moles to Grams Calculator
Convert moles to mass in grams using the molecular weight of your substance. Formula: m = n × MW.
How to Convert Moles to Grams
- Find the molecular weight (MW) of your substance from the periodic table or the table below.
- Multiply the number of moles by the molecular weight.
- The result is the mass in grams.
Example: You need 0.25 mol of NaOH. How many grams?
m = 0.25 mol × 40.00 g/mol = 10.00 g
Moles to Grams Formula
Where:
- m = mass (grams)
- n = number of moles (mol)
- MW = molecular weight (g/mol)
Practical Example
A common lab task is to prepare a given amount of solute for a solution:
Problem: You need 0.1 mol of glucose (C₆H₁₂O₆, MW 180.16 g/mol) for an experiment. How many grams should you weigh?
Solution:
m = 0.1 mol × 180.16 g/mol = 18.016 g
Weigh 18.016 g of glucose on a balance, then dissolve in solvent.
Common Molecular Weights
Click any row to use that molecular weight in the calculator above.
| Compound | Formula | MW (g/mol) |
|---|---|---|
| Water | H₂O | 18.015 |
| Sodium chloride | NaCl | 58.44 |
| Sodium hydroxide | NaOH | 40.00 |
| Hydrochloric acid | HCl | 36.46 |
| Sulfuric acid | H₂SO₄ | 98.08 |
| Nitric acid | HNO₃ | 63.01 |
| Glucose | C₆H₁₂O₆ | 180.16 |
| Ethanol | C₂H₅OH | 46.07 |
| Acetic acid | CH₃COOH | 60.05 |
| Carbon dioxide | CO₂ | 44.01 |
| Calcium carbonate | CaCO₃ | 100.09 |
| Sucrose | C₁₂H₂₂O₁₁ | 342.30 |
Frequently Asked Questions
How do I convert moles to grams?
Multiply the number of moles by the molecular weight in g/mol. Formula: mass = moles × MW.
Example: 0.5 mol NaCl × 58.44 g/mol = 29.22 g.
What is the formula for moles to grams?
m = n × MW, where m is mass in grams, n is moles, and MW is molecular weight in g/mol. It is the inverse of the grams-to-moles formula n = m ÷ MW.
How many grams in 1 mole?
The mass of 1 mole equals the molecular weight in grams:
- Water (MW 18.015): 1 mol = 18.015 g
- NaCl (MW 58.44): 1 mol = 58.44 g
- Glucose (MW 180.16): 1 mol = 180.16 g
What is molecular weight?
Molecular weight is the mass of one mole of a substance in g/mol. It is calculated by summing the atomic masses of all atoms in the chemical formula from the periodic table.
How do I prepare a solution of N moles?
First calculate the mass needed using mass = moles × MW. Then weigh that mass on a balance, dissolve it in solvent, and dilute to the target volume. Use our Molarity Calculator to compute volume and concentration directly.
Related Chemistry Tools
- Grams to Moles Calculator — reverse conversion
- Molarity Calculator — uses moles + volume to compute concentration
- Dilution Calculator (M₁V₁ = M₂V₂)
- All Chemistry Calculators
All calculations on CoolConversion use formulas and constants documented by internationally recognised standards bodies (such as IUPAC and NIST).
