Molarity & Dilution Calculator

How to use

1. 1Choose Molarity to work with a single solution, or Dilution to plan a dilution with C1V1 = C2V2.
2. 2Pick which variable to solve for; that field locks and the rest become inputs.
3. 3Type the known values and select a unit for each (mass, volume, and concentration each support several scales).
4. 4Read the solved value and the extra detail, such as moles of solute, solvent to add, dilution factor, and a recipe.
5. 5Press Copy result to grab the answer, or Reset to clear the fields back to the example values.

About this tool

Molarity & Dilution Calculator solves the two most common solution-chemistry questions in one place: how concentrated a solution is, and how to dilute it. In molarity mode you give any three of four quantities, molarity, mass of solute, molar mass, and volume of solution, and the tool solves for the fourth using the standard relationships molarity = moles / litres and moles = mass / molar mass. Pick which variable to solve for and the matching field locks so the inputs stay unambiguous. Mass accepts grams, milligrams, micrograms, and kilograms; volume accepts litres, millilitres, and microlitres; concentration accepts molar, millimolar, micromolar, and nanomolar. Every input is converted to base SI units before the math runs, so you can freely mix grams with millilitres and read the answer back in whatever scale is convenient, including the moles of solute the result implies. The molar mass is entered directly rather than parsed from a formula, which keeps the tool fast and predictable; if you need the molar mass of a compound, the related Molar Mass Calculator works it out from a formula like NaCl or C6H12O6. Dilution mode applies the conservation rule C1 V1 = C2 V2, where C is concentration and V is volume of the stock and final solutions. Choose any one of C1, V1, C2, or V2 to solve for, and the tool returns the missing value plus the volume of solvent to add, the dilution factor, and a plain-language recipe such as take 50 mL of 1 M and dilute to 500 mL. Non-physical inputs are caught with clear messages, and the tool warns when the numbers describe concentrating rather than diluting, for example a final concentration higher than the stock, which cannot be reached by adding solvent. All results are based on ideal-solution arithmetic and assume the solute fully dissolves; they are a planning aid for coursework and routine lab prep, not a substitute for a validated protocol. Every value is computed locally in your browser, so the numbers you enter are never uploaded or logged.

Free to use. Works in your browser. No signup, no login.