Molarity Calculator

Solve for

Molarity (mol/L) Moles of solute (mol) Volume of solution (L)

Molarity —

Molarity (M) = moles of solute ÷ liters of solution. Need moles from a compound's mass instead? Use the Molecular Weight Calculator to convert grams to moles first.

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Free molarity calculator that solves for molarity, moles of solute, or solution volume from the other two — using M = mol/L from any direction.

How it works

Choose what you want to solve for: molarity, moles, or volume
Enter the other two values
See the result instantly

Frequently asked questions

I have grams, not moles — now what?

Use the Molecular Weight Calculator to convert your compound's mass in grams to moles first (moles = grams ÷ molecular weight), then use that result here.

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From the blog

unit-convert

Molarity, moles, or volume — this calculator works backward from whichever two you know

M = mol/L only helps if you already know two of the three. Rearranging it under lab-report pressure is exactly when mistakes happen.

2026-09-02

Update history

2026-09-02 Launched: molarity calculator that solves for molarity, moles, or volume (M = mol/L). Entirely client-side.