Free tool

Molarity Calculator

Solve for mass, volume, or molar concentration. Type a chemical formula and the molecular weight fills itself in.

Required mass
5.844 mg

0.0058 g of a 58.44 g/mol compound for 100 mL at 1 mM

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We build verifiable AI for regulated biotech work. These bench tools are free — no account, no email, no tracking wall.

  • Deterministic math, shown in the open
  • Runs entirely in your browser
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Method notes

Assumes an ideal dilute aqueous solution where the solute volume is negligible. For concentrated stocks, prepare to volume rather than adding a fixed solvent volume.

Molarity, step by step

The core equation

mass (g) = C (mol/L) × V (L) × MW (g/mol)

Every mode on this page is just that equation rearranged.

Watch your units

The most common bench error is mixing mL with L or µM with mM. Pick the units in the dropdowns and the conversion is handled for you.

Hydrates and salts

Use the molecular weight of the exact reagent on the bottle, including waters of crystallization. Anhydrous and hydrated forms can differ by 30% or more.

Purity correction

If the certificate of analysis says 95% purity, divide the calculated mass by 0.95 to hit your target concentration.

What Quandra v8 adds

These calculators give you one number at a time. Quandra v8 writes the statistical analysis plan, generates R/SAS code, cross-checks assumptions against a locked reference corpus, and keeps an audit trail for regulated work.