Vial Concentration Calculator

Inputs

Compound sizes and prices come from the live catalog. Leave the compound unset to enter a mass by hand.

Formula: concentration = mass ÷ volume. Assumes complete dissolution and no volume displacement by the solute. Reference for laboratory solution preparation and record-keeping only.

sizes and price per milligram

Open the product record → · identity, purity, certificates and what published research does and does not establish all live there.

What this calculator computes, and what it cannot

Concentration is mass divided by volume — the simplest equation in solution work, and the number most often recorded wrong because it silently changes whenever either input does. Given a vial's labeled peptide mass and the diluent volume added, this page reports mg/mL and µg/mL, plus a per-graduation table so a laboratory record can state what any drawn volume contained at preparation time.

Worked through once, with a vial from this catalog. A 50mg vial of 5-AMINO-1MQ holds 50 mg. Add 2 mL of diluent and the solution is 25.00 mg/mL, which is 25,000 µg/mL — the same figure in the units a small volume is usually recorded in. Draw 0.25 mL of that and you have moved 6.25 mg of peptide. Halve the diluent to 1.0 mL and every one of those numbers doubles, which is the whole reason a concentration has to be written down beside the volume that produced it rather than inferred later from the vial size.

Two assumptions print beside the result because they are assumptions: complete dissolution (the arithmetic trusts every labeled milligram into solution), and negligible solute volume (at research masses, diluent volume stands in for solution volume). Neither correction matters at these quantities; both would at scale.

The calculator only ever asks for a volume, never for what the liquid is. In laboratory solution preparation the diluent added to a lyophilized vial is usually bacteriostatic water — water carrying 0.9% benzyl alcohol as a preservative — or plain sterile water where nothing is drawn twice. The arithmetic is indifferent to which: concentration is the mass in the vial divided by the volume added, whatever that volume is made of. The choice changes how long a prepared solution stays usable, not what its concentration is, and it is covered in the bacteriostatic water guide. Both grades are stocked as BAC Water in 3 mL and 10 mL.

What it deliberately does not do: nothing here concerns administration, and the label mass is nominal — the measured net content for a specific lot lives on that lot's certificate of analysis, which is the number a careful record uses instead.