Molarity calculator
Find molarity from mass and molar mass, moles from mass, or the mass needed for a target concentration; 10 g NaCl (58.44 g/mol) in 1 L ≈ 0.171 mol/L.
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- No upload
- Instant result
Assumptions & formula
Formula and assumptions
n=m/M; c=n/V; m=cVM; mol, g, g/mol, L
Use mass in grams, molar mass in g/mol, amount in mol and volume in L or mL. This is a formula calculation, not a laboratory procedure or safety instruction.
Results
Enter values and press Calculate to see the result here.
How to use this calculator
- Set inputs and units
Choose mass, moles or solution mode. Where required, enter the solution volume in L/mL and the molar mass in g/mol.
- Calculate
Check this worked example: mass=10 g, molarMass=100 g/mol, solutionVolume=500 mL → n=0.1 mol, c=0.2 mol/L
- Results
Concentration divides moles by the final solution volume in liters, not by the initial solvent volume.
Questions and limits
Does the tool derive molar mass from a formula?
No. Supply the molar mass of the right chemical species yourself, including any hydrate or purity considerations, which are outside this arithmetic.
Which input errors should I correct?
The volume and the required molar mass must be positive. Confusing 500 mL with 500 L causes a thousandfold error.
What does this calculation leave out?
Stoichiometric unit arithmetic only. It is not a safety procedure for preparing solutions, a guide to medical dosing, an activity model or a purity correction.