What is the Molarity Calculator?
Molarity (M) tells you how many moles of solute are dissolved in each liter of solution — the most common concentration unit in general chemistry. The relationship is simple: M = n / V, where n is moles and V is volume in liters. This calculator solves for any one of the three variables, or finds molarity from solute mass when you enter a chemical formula. Switch between liters and milliliters, use example presets for quick homework checks, and copy results for your lab notes. Everything runs in your browser with no signup.
How to use the Molarity Calculator
- Pick what to solve: molarity from moles, molarity from mass, moles from M and V, or volume from M and n.
- Enter the known values (and a formula for mass-based molarity).
- Choose L or mL for volume.
- Read molarity in mol/L plus moles and volume.
- Copy the summary if you need it for homework or lab prep.
Common use cases
- Finding molarity after dissolving 0.5 mol of solute in 2 L of water
- Calculating moles in 500 mL of 0.25 M solution
- Determining volume needed to dissolve 2 mol at 1 M concentration
Frequently asked questions
- What is the molarity formula?
- M = n / V, where M is molarity (mol/L), n is moles of solute, and V is volume of solution in liters.
- How do I find molarity from grams?
- First convert mass to moles using n = m / M_r (molar mass), then divide by volume in liters. This tool does both steps when you enter formula, mass, and volume.
- Is this different from the Solution Concentration Calculator?
- This tool focuses on the core M = n / V relationship. The Solution Concentration Calculator also covers target mass prep and dilution (C₁V₁ = C₂V₂).
