Four calculators, one panel.
Pick a mode below — mix and match units freely, everything recalculates live as you type, and every result explains itself.
How much solute you're dissolving.
The molar mass of the solute — e.g. NaCl ≈ 58.44 g/mol.
The total volume the solute is dissolved into.
The molarity you want the final solution to have.
The total volume you plan to make.
The molar mass of the solute.
The molarity you want the final solution to have.
How much solute you have on hand.
Must be greater than zero, and molarity must be non-zero, to solve for volume.
Concentration of the stock solution before dilution.
Volume of stock solution taken.
Concentration of the solution after dilution — this is what you're solving for.
Total volume of the solution after topping up with solvent.
Two or three inputs to an answer.
No manual required — but here's the entire flow in four moves.
Pick a mode
Molarity for mass + molar mass + volume → mol/L. Solve mass or Solve volume for the two reverse cases. Dilution for M₁V₁=M₂V₂, solving for any one of the four values.
Enter what you know
Type a number and pick its unit from the dropdown next to it — mix grams with litres, or millilitres with mmol/L, it's all converted automatically. The example chips fill everything in with one tap.
Read the results
The main answer sits up top in large type. Related values in other units sit below, and the exact formula with your numbers substituted sits at the bottom.
Trust the checks
Impossible inputs — negative mass, a zero volume or molarity you're trying to divide by — get flagged with a plain-English reason instead of a wrong or broken answer. Copy any result set with one click.
Two formulas, four ways to use them.
Every mode above comes from the same two equations, just solved for a different letter.
Molarity
Mass in grams, molar mass in g/mol, volume in litres — molarity comes out in mol/L.
Solving for mass or volume
Rearrange the molarity formula to find how much solute to weigh out, or how much solution to make.
Dilution
Moles of solute don't change on dilution, so knowing any three of the four values gives you the fourth.
Questions people actually ask.
The short answers — with the long ones one tap away.
What is the formula for molarity?+
Molarity is M = n ÷ V, where n is moles of solute and V is volume of solution in litres. Since moles equal mass divided by molar mass, this is often written M = mass ÷ (MW × V). 5.85 g of NaCl (MW 58.44 g/mol) in 0.5 L gives M = 5.85 ÷ (58.44 × 0.5) ≈ 0.2 mol/L.
How do I calculate the molarity of a solution?+
Enter the mass of solute, its molar mass, and the volume of solution in the Molarity tab, in whatever units you have — grams or pounds, litres or millilitres. The calculator converts everything to grams and litres, applies the formula, and shows the answer in mol/L, mmol/L and µmol/L.
How do I find the mass of solute needed for a target molarity?+
Rearrange the formula: mass = M × V × MW. Enter the target molarity, the volume of solution, and the molar mass in the Solve mass tab and the calculator returns the mass needed in grams, milligrams, kilograms, pounds and ounces.
How do I find the volume needed for a target molarity?+
Rearrange the formula: V = mass ÷ (M × MW). Enter the target molarity, the mass of solute, and the molar mass in the Solve volume tab and the calculator returns volume in litres, millilitres, microlitres and gallons.
What is the dilution formula M₁V₁ = M₂V₂?+
It relates a stock solution to a diluted one: M₁ and V₁ are the concentration and volume before dilution, M₂ and V₂ are the concentration and volume after. Moles of solute stay the same during dilution, so knowing any three values gives you the fourth. The Dilution tab lets you pick which one to solve for.
What units is molarity measured in?+
Molarity is measured in moles per litre (mol/L), written as M. Dilute solutions are often given in millimoles per litre (mmol/L, or mM) or micromoles per litre (µmol/L, or µM) — every concentration field in this tool switches between all three.
Is this tool free, and where does my data go?+
It's completely free and runs entirely in your browser — nothing you type is uploaded, logged, or sent to any server. No account, no sign-up, no limits.