Percentage Strength Of Preparation Calculator

Work out percentage strength of preparation instantly with clear inputs, formula shown and shareable results.

About Percentage Strength Of Preparation Calculator

Expresses a preparation's strength as percentage weight in volume, mg/mL and ratio strength, the three notations used on pharmacy labels.

Formula

Percentage strength

% w/v = grams of solute per 100 mL of preparation; mg/mL = % w/v x 10; ratio strength = 1 in (volume / mass)

Worked example

With the default values below, Percentage Strength Of Preparation Calculator returns Percentage strength w/v of 2.5000%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Mass of active ingredientaccepts 0.001–1,000 g: 5 g
Total volume of preparationaccepts 0.1–10,000 mL: 200 mL

Results

Percentage strength w/v: 2.5000%
Concentration: 25.000 mg/mL
Ratio strength: 1 in 40
Concentration: 25.000 g/L

Step by step

1Values used
2Percentage strength
3Percentage strength w/v= 2.5000
4Concentration= 25.000 mg/mL
5Ratio strength= 1 in 40
6Concentration= 25.000 g/L

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

What is the difference between w/v and w/w?

Weight in volume uses grams per 100 mL of solution; weight in weight uses grams per 100 g of preparation, used for ointments.

Why is ratio strength still used?

Adrenaline and some antiseptics are traditionally labelled as ratio strengths such as 1 in 1000.