Molarity Calculator
Calculate molarity from moles and volume, or from mass, molar mass, and total solution volume.
Use the direct molarity formula when you already know moles of solute and total solution volume.
0.5 M
500 mM
About the molarity calculator
How this calculator works
Molarity is easier to trust when the calculator shows the exact pathway from the inputs to the concentration, whether you start from moles or from mass and molar mass.
This page keeps both common chemistry workflows in one place so you can switch methods without opening a separate tool.
Where it is useful
It is useful for classroom chemistry, lab preparation, dilution planning, and quick concentration checks.
The variant-based generic widget also makes it a good example of when a registry calculator fits better than a pair converter or text transform.
- Calculate solution concentration from known moles and volume.
- Convert mass into molarity when molar mass is known.
- Check M and mM values quickly during chemistry work.
Example calculations
3 examples0.25 mol in 0.5 L
0.5 M
58.44 g NaCl, 58.44 g/mol, 1 L
1 M
0.1 M
100 mM
equivalent
Common uses
3 ideas- Calculate solution concentration from known moles and volume.
- Convert mass into molarity when molar mass is known.
- Check M and mM values quickly during chemistry work.
FAQ
3 answersWhat is molarity?
Molarity is moles of solute divided by liters of total solution, usually written as mol/L or simply M.
When should I use each molarity mode?
Use the moles variant when the amount of solute is already known in moles. Use the mass variant when you need to convert grams into moles first using molar mass.
Why does the molarity calculator require a non-zero volume?
Solution volume must be greater than zero because molarity divides the amount of solute by the total volume.