Using the Molarity Calculator
Use grams for mass and grams per mole for molar mass. The volume is the final solution volume, not simply the solvent volume before dissolving the solute. Both molar mass and volume must be positive.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Solute mass (g)
- 5.844
- Molar mass (g/mol)
- 58.44
- Final solution volume (L)
- 1
Example result
- Molarity (mol/L)
- 0.1
- Amount of substance (mol)
- 0.1
Method and assumptions
Moles = mass / molar mass; molarity = moles / final solution volume.
Check the chemical identity and units
Chemical calculations require the formula and amount to describe the same substance. A different chemical form can have a different molar mass even when the common product name sounds similar. Keep grams, moles and liters distinct, and use the final quantity specified by the equation. This page performs arithmetic rather than validating a laboratory procedure.
Common question
Why does final solution volume matter?
Molarity is defined per liter of solution. Adding solute to a measured solvent volume does not automatically establish that same final solution volume. Use the final volume appropriate to the preparation or measurement you are modeling.
Guide updated .