Percent Solution Calculator (w/v, v/v, w/w)

How it works

% w/v: solute (g) = % × final volume (mL) ÷ 100 · % v/v: solute (mL) = % × final volume (mL) ÷ 100 · % w/w: solute (g) = % × final mass (g) ÷ 100, solvent (g) = final mass − solute · 1% w/v = 10 mg/mL = 10 g/L

Percent solutions are the everyday concentration unit of the lab bench and the pharmacy. Weight/volume (w/v) percent is grams of solute in 100 mL of final solution — 0.9% saline has 0.9 g of sodium chloride per 100 mL, and a 1% agarose gel 1 g per 100 mL. Volume/volume (v/v) is used for liquids such as 70% ethanol, and weight/weight (w/w) for ointments, creams and concentrated acids. For w/v and v/v the solute is always made up to the final volume, not added to it, because the solute itself takes up space.

Worked example

To make 100 mL of a 10% w/v solution, weigh 10 × 100 ÷ 100 = 10 g of solute, dissolve it in less than 100 mL of solvent and then make up to 100 mL. The solution contains 100 mg/mL (100 g/L).

Sources: Wikipedia — Concentration (mass, volume and percent) · Wikipedia — Mass fraction (w/w)

Frequently asked questions