Free tool · Concentration only
Enter the compound mass in the vial and the bacteriostatic water you plan to add. This returns the exact solution concentration in mg/mL and mcg per 0.1 mL — the concentration math, nothing more.
At 10 mg in 2 mL, the solution is 5 mg/mL.
Reconstitution concentration is a single division: the mass of compound already in the vial divided by the volume of bacteriostatic water you add. The mass is fixed the moment the vial was filled — adding water never changes how much compound is present, only how concentrated the resulting solution is.
Concretely, 10 mg of a lyophilized peptide reconstituted in 2 mL of bacteriostatic water yields 5 mg/mL. Expressed on a finer scale that is 500 mcg in every 0.1 mL of solution. Add more water — say 4 mL — and the same 10 mg now reads 2.5 mg/mL. The calculator above performs exactly this division and also expresses the answer per 0.1 mL, which is the resolution researchers usually plan a dilution around.
This is concentration only. It deliberately does not convert a target quantity into a volume to withdraw, and it does not translate anything into syringe units — that is outside what a concentration tool should assert.
Common vial masses across common bacteriostatic water volumes. Every cell is the resulting concentration in mg/mL (compound mass ÷ water volume).
| Compound ↓ / Water → | 1 mL | 2 mL | 3 mL | 5 mL |
|---|---|---|---|---|
| 5 mg | 5 | 2.5 | 1.67 | 1 |
| 10 mg | 10 | 5 | 3.33 | 2 |
| 15 mg | 15 | 7.5 | 5 | 3 |
| 20 mg | 20 | 10 | 6.67 | 4 |
| 30 mg | 30 | 15 | 10 | 6 |
Read a cell as milligrams of compound per millilitre of finished solution. To see a value per 0.1 mL, move the decimal: 5 mg/mL = 500 mcg per 0.1 mL.
For the overwhelming majority of lyophilized research peptides the correct diluent is bacteriostatic water — sterile water with 0.9% benzyl alcohol, which preserves a multi-dose vial through repeated draws. A minority of poorly soluble compounds are instead brought into solution with dilute acetic acid or plain sterile water; the compound's own solubility profile decides. The difference between these diluents is covered in bacteriostatic vs sterile water and bacteriostatic vs acetic acid water.
Whatever the diluent, the concentration math above is identical: mass in the vial over volume added.
Concentration equals the mass of compound in the vial divided by the volume of bacteriostatic water added. For example, 10 mg reconstituted in 2 mL gives 5 mg/mL, which is the same as 500 mcg per 0.1 mL. The calculator does this division for you and also expresses the result per 0.1 mL.
The standard laboratory diluent is bacteriostatic water — sterile water with 0.9% benzyl alcohol so the multi-dose vial can be re-entered. Some poorly soluble compounds instead use dilute acetic acid or sterile water; the compound's solubility profile determines which.
No. The total mass of compound in the vial is fixed. Adding more bacteriostatic water spreads that same mass through a larger volume, lowering the concentration; adding less water raises it. The calculator shows exactly how concentration shifts with the volume you choose.
No. It reports solution concentration only, for planning a laboratory dilution. It does not convert a target dose into a volume to draw, does not output syringe units, and is not dosing guidance. All compounds referenced are sold strictly for laboratory research use only.
For laboratory and research use only. Not for human or animal consumption. This calculator reports solution concentration for planning a laboratory dilution; it is not medical advice, not dosing guidance, and does not tell you how much of any substance to administer. Intended for qualified researchers 18+.