Molarity Calculator

This calculator is useful when you know how much chemical you have and how much solution you’re making, but you’re unsure about the final concentration. This comes up a lot in labs, classrooms, and even DIY chemistry setups where precise mixing matters.

Instead of stopping to manually convert units or double-check math, you can enter your values and instantly see the concentration, number of moles, and how everything relates to each other.

Who this calculator is for

This tool is especially helpful for students preparing solutions for experiments, lab technicians working with different unit systems, and anyone who needs to move between mass, volume, and concentration without mistakes.

It’s also useful if you’re checking someone else’s numbers or trying to understand whether a prepared solution is stronger or weaker than expected.

How the calculation works

The calculator first converts everything into a common base: mass into grams, molecular weight into grams per mole, and volume into liters. This step happens automatically, even if you choose uncommon units.

Once that’s done, it figures out how many moles of solute you have from the mass and molecular weight. That mole value is then divided by the solution volume to get the concentration.

Because everything updates live, changing the mass, volume, or molecular weight immediately shows how the concentration and moles respond.

One realistic example

Suppose you dissolve 100 grams of sodium chloride in 2 liters of water, and the molecular weight is 58.44 g/mol.

The calculator converts the mass into moles, divides by the volume, and shows a concentration of about 0.855 molar. You can also see the exact number of moles and confirm that the mass and concentration are consistent.

Common assumptions and limitations

The volume entered is assumed to be the final solution volume, not just the solvent added.
The calculator does not account for temperature effects or volume changes after mixing.
Extremely small or very large values may be rounded for readability.
Concentration units are displayed, but internal calculations are based on molarity.

If your result seems off, double-check that the molecular weight matches the compound you’re using and that the volume reflects the final mixture, not the starting liquid.