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Pharmacy Unit Conversion Calculator

Convert between pharmacy concentration units (% w/v, % w/w, mg/mL, mg/g, mcg/mL, mcg/g) with automatic density adjustments.

Disclaimer: This tool is provided for informational and educational purposes only. Results should always be independently verified by a qualified healthcare professional before use in clinical practice. Compound Direct accepts no liability for errors or clinical decisions made based on these calculations.

Used only for converting between w/v and w/w. Default is 1.0 for water-based solutions.

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Enter a value and select a unit to see conversion results

How to Use This Tool

  1. Enter a numeric value in the input field
  2. Select the unit that your value is in
  3. Optionally adjust the density (in g/mL) if converting between w/v and w/w units. For aqueous solutions, use 1.0 g/mL. For oils or other solutions, look up the specific gravity of your solvent.
  4. View the equivalent values in all other units in the results card below

Tip: Use this tool when creating compound formulations to ensure your ingredients are measured in the correct unit for the recipe.

Formula & Methodology

Percentage (% w/v) to mg/mL

1% w/v = 10 mg/mL

Example: 5% w/v = 50 mg/mL

Percentage (% w/w) to mg/g

1% w/w = 10 mg/g

Example: 0.5% w/w = 5 mg/g

Micrograms (mcg/mL or mcg/g)

1% w/v = 10,000 mcg/mL

1% w/w = 10,000 mcg/g

Example: 0.1% w/v = 1,000 mcg/mL

Weight/Volume to Weight/Weight Conversion

% w/w = % w/v ÷ density (g/mL)

% w/v = % w/w × density (g/mL)

The density field (default 1 g/mL for aqueous solutions) is used to convert between w/v and w/w units.

Frequently Asked Questions

What is the difference between % w/v and % w/w?
% w/v (weight/volume) is the mass of solute per total volume of solution (used for liquids). % w/w (weight/weight) is the mass of solute per total mass of preparation (used for solids or when you know the total weight). They differ when the solution density is not 1.0 g/mL.
When should I use % w/v vs % w/w?
Use % w/v when working with liquid formulations where the total volume is known. Use % w/w when working with solid preparations or when the total weight is known. For capsules, use % w/w. For solutions, use % w/v.
What density should I use?
For aqueous (water-based) solutions, use 1.0 g/mL. For oils or organic solvents, look up the specific gravity in a reference guide. For mixed solvents, calculate the average density. Density is only used when converting between w/v and w/w units.
Can I use this for clinical pharmacy dosing?
Yes! This tool is useful for verifying medication concentrations, converting between different strength labels, and checking that prepared solutions have the correct concentration. Always double-check critical calculations with a colleague.
What is mcg/mL or mcg/g?
mcg (microgram) is 1/1000 of a mg. These units are used for very potent medications or substances where ng/mL precision is needed. 1% w/v = 10,000 mcg/mL and 1% w/w = 10,000 mcg/g.

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