Reconstitution Calculator
Lyophilised powder tells you nothing about the solution it becomes. Enter the mass in the vial and the volume of diluent, and this returns the concentration — the same figure in the three units a bench reads it in.
Enter a mass and a volume above. Both must be greater than zero.
Working backwards from a target concentration
The more common bench question is the other one: you know the concentration you want to end up at, and you need the volume of diluent that gets you there. Same equation, rearranged.
The arithmetic, in full
There is no trick in it. Concentration is mass divided by volume:
C (mg/mL) = mass (mg) ÷ volume (mL)
Everything else is unit conversion. 1 mg is 1,000 mcg, so multiplying the milligram figure by a thousand gives micrograms per millilitre. The finest graduation on the graduated equipment these solutions are measured with is 0.01 mL, so dividing again by a hundred gives the mass sitting in one graduation.
A worked example
A 10 mg vial reconstituted with 2 mL of diluent gives 10 ÷ 2 = 5 mg/mL. That is 5,000 mcg/mL, and 50 mcg in each 0.01 mL graduation. Reconstitute the same vial with 1 mL instead and every one of those figures doubles — the powder has not changed, only what it is dissolved in.
Why the numbers here are not padded with zeros
A 10 mg vial in 3 mL is 3.333 mg/mL, not 3.33 and not 3.3333333. This calculator rounds to four significant figures and drops trailing zeros, because a decimal place you did not measure is a claim about precision you do not have. The vial mass is a nominal fill; the equipment you measured the diluent with has a tolerance of its own. Four figures is already generous.
Handling notes
- Direct the diluent down the wall of the vial rather than onto the powder cake. Peptides are surface-active, and a stream driven straight into the cake will foam it.
- Swirl or leave it to dissolve. Do not shake — agitation denatures peptides and the foam it produces takes the material with it.
- Bacteriostatic water contains benzyl alcohol as a preservative; sterile water does not. Which is appropriate depends on the protocol and on how long the solution needs to hold, and that is the researcher's call, not ours.
- Reconstituted solutions are refrigerated, kept out of light, and treated as having a far shorter working life than the lyophilised powder they came from. The vial label and the certificate of analysis govern.
- Label the vial the moment it is reconstituted — compound, lot, concentration, date. An unlabelled vial in a fridge is an unknown within a week.
Every lot we ship is tested by an independent third-party laboratory first, then tested again in our own laboratory when it arrives, and the certificate for your exact lot is filed against your order. The mass on the label is the mass this calculator is dividing — see how we verify it.
This calculator performs unit arithmetic only. It does not recommend, calculate, or imply a dose, and it must not be read as guidance on the use of any compound. All products supplied by Alpha Aminos are for laboratory research use only and are not for human or animal consumption. No statement on this page has been evaluated by the Food and Drug Administration, and nothing here is intended to diagnose, treat, cure, or prevent any disease.