Solution strength calculator
The volumes that make up a solution at a target concentration, and what it actually came out at.
This is arithmetic about volumes. It says nothing about sterility, filtration or contamination, which are what actually cause harm here — and getting the numbers right does not make an unsterile preparation safe.
Carrier oil118.5 ml
Benzyl alcohol4 ml
Benzyl benzoate40 ml
Powder displaces37.5 ml
Finished volume200 ml
Show the working
- Powder
- 50 g = 50000 mg
- Finished volume
- 50000 mg ÷ 250 mg/ml = 200 ml
- Benzyl alcohol (2%)
- 200 ml × 2% = 4 ml
- Benzyl benzoate (20%)
- 200 ml × 20% = 40 ml
- Powder displaces (0.75 ml/g)
- 50 g × 0.75 = 37.5 ml
- Carrier oil
- 200 − 4 − 40 − 37.5 = 118.5 ml
The displacement figure above is an assumption, not a measurement. If the finished volume comes out different from the figure here, the measured volume is the true one and the strength should be recalculated from it.