Molarity Calculator — Moles, Mass and Solutions

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How many grams make a 1 M solution? Mass ↔ moles ↔ molarity, any direction.

Solve for Mass of solute (g) Molarity (M) Volume (L)

Molar mass (g/mol)

Molarity (mol/L)

Volume (L)

Mass (g)

Common molar masses: NaCl 58.44 · glucose 180.16 · KOH 56.11 · CaCO₃ 100.09 (g/mol).

How to use this tool

1. Choose what to solve for — mass, molarity or volume.
2. Enter the molar mass from the label (or the sum of atomic weights).
3. Fill the two known remaining fields and press Calculate.

Example

0.5 L of 0.1 M NaCl: mass = 0.1 × 0.5 × 58.44 = 2.92 g — weigh 2.92 g, dissolve, top up to exactly 500 mL.

The formula

moles = molarity × volume  |  mass = moles × molar mass

What the result means

Molarity counts particles, not grams — one mole is 6.022 × 10²³ molecules, which is why chemists weigh by molar mass: it makes different substances comparable by the number of molecules, not by the number on the scale.

Frequently asked questions

Where do I find the molar mass?

On every reagent bottle label. Or compute it: sum the atomic weights from the formula (NaCl = 22.99 + 35.45 = 58.44 g/mol).

Why does volume use litres?

Because molarity is defined as moles per litre. Working in mL everywhere is fine — just convert: 250 mL = 0.25 L.

Molarity vs molality?

Molarity is per litre of solution; molality is per kilogram of solvent. Molarity rules the typical bench; molality appears when temperature changes volume.

Is my lab data private?

Yes — the calculation happens in your browser.

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