Peptide Reconstitution Calculator

Enter the peptide mass in a lyophilized vial and the volume of bacteriostatic water you add. The tool returns the concentration of the resulting research reference solution and how much peptide sits in each aliquot volume.

Research use only. This is laboratory concentration arithmetic for handling a research reference solution. It is not a dose, a dosing schedule, or a route of administration, and nothing here is medical advice. Always use the peptide mass reported on the lot's third-party COA, not the number printed on the cap.

Concentration

Vial mass and solvent in, mg/mL out.

Peptide mass in the vial

Bacteriostatic water added

Concentration

5 mg/mL

= 5,000 mcg/mL

Solvent needed

Vial mass and a target concentration in, mL out.

Peptide mass in the vial

Target concentration

mg/mL

Bacteriostatic water to add

2 mL

for a 10 mg vial at 5 mg/mL

Peptide mass per aliquot

Based on the Concentration panel above (5 mg/mL). Aliquot = the volume of solution you draw; this is the peptide mass it contains, RUO.

Aliquot volume	Peptide mass	Micrograms

Static reference matrix: concentration by vial mass and solvent volume

These figures are precomputed and fixed, so they read the same whether or not the calculator above is used. Every cell is vial mass (mg) ÷ bacteriostatic water (mL), giving the mg/mL concentration of the reconstituted research reference solution. Research use only, laboratory arithmetic, no human-use guidance.

Concentration in mg/mL for common vial masses reconstituted with 1 to 5 mL
Vial mass	1 mL water	2 mL water	3 mL water	5 mL water
2 mg vial	2 mg/mL	1 mg/mL	0.667 mg/mL	0.4 mg/mL
5 mg vial	5 mg/mL	2.5 mg/mL	1.667 mg/mL	1 mg/mL
10 mg vial	10 mg/mL	5 mg/mL	3.333 mg/mL	2 mg/mL
15 mg vial	15 mg/mL	7.5 mg/mL	5 mg/mL	3 mg/mL
20 mg vial	20 mg/mL	10 mg/mL	6.667 mg/mL	4 mg/mL
30 mg vial	30 mg/mL	15 mg/mL	10 mg/mL	6 mg/mL

Second table: a single 10 mg vial taken to five common concentrations, with the peptide mass contained in standard aliquot volumes. An aliquot here is simply the volume of solution drawn from the vial for handling or analysis; the mass shown is what that volume contains, computed as concentration (mg/mL) × aliquot volume (mL).

10 mg vial: peptide mass per aliquot volume, mg with mcg beneath
Reconstitution	0.05 mL	0.10 mL	0.20 mL	0.25 mL	0.50 mL	1.00 mL
10 mg/mL10 mg + 1 mL water	0.5 mg500 mcg	1 mg1,000 mcg	2 mg2,000 mcg	2.5 mg2,500 mcg	5 mg5,000 mcg	10 mg10,000 mcg
5 mg/mL10 mg + 2 mL water	0.25 mg250 mcg	0.5 mg500 mcg	1 mg1,000 mcg	1.25 mg1,250 mcg	2.5 mg2,500 mcg	5 mg5,000 mcg
3.333 mg/mL10 mg + 3 mL water	0.167 mg167 mcg	0.333 mg333 mcg	0.667 mg667 mcg	0.833 mg833 mcg	1.667 mg1,667 mcg	3.333 mg3,333 mcg
2.5 mg/mL10 mg + 4 mL water	0.125 mg125 mcg	0.25 mg250 mcg	0.5 mg500 mcg	0.625 mg625 mcg	1.25 mg1,250 mcg	2.5 mg2,500 mcg
2 mg/mL10 mg + 5 mL water	0.1 mg100 mcg	0.2 mg200 mcg	0.4 mg400 mcg	0.5 mg500 mcg	1 mg1,000 mcg	2 mg2,000 mcg

Values are rounded to three decimal places for mass in mg and to whole micrograms. They assume the peptide mass stated on the lot's third-party COA is the true mass, and they ignore the small volume the lyophilized powder itself occupies. Research use only.

The math, in one line

concentration (mg/mL) = peptide mass in the vial (mg) ÷ bacteriostatic water added (mL). Adding more water makes a more dilute solution of the same fixed mass; the total peptide in the vial never changes, only its concentration. To hit a target concentration, invert it: water (mL) = mass (mg) ÷ target (mg/mL).

The single number this whole calculation depends on is the peptide mass, and the only trustworthy source for that is a lot-matched third-party COA. The “10 mg” on a cap is a manufacturing target; if the lot's COA reports a different measured mass, use that. Learn how to read a peptide COA and why bacteriostatic water is the usual multi-draw solvent.

Disclosure: coaindex is affiliated with Pepora and earns a commission on code UTILITY15. Pepora is scored on the same published criteria as every other supplier in our vendor table at /vendors, where it currently does not rank first.

The mass you type in is only as real as the COA behind it.

Pepora publishes independently verifiable third-party COAs (Freedom Diagnostics, HPLC plus mass spec) you can look up by accession before you buy, so the mass in this calculator is a checked figure rather than a label guess. It ships from the US.

See Pepora's verifiable COAs

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