Reconstitution calculator.
Mass in, volume in, concentration out — with molarity when you need it. The arithmetic of preparing a stock solution, done for you and shown honestly.
Reconstitution arithmetic is simple and unforgiving: the concentration of a stock solution is the peptide mass divided by the solvent volume, and every downstream number in an experiment inherits it. The calculator below does the division, converts the units, and — given a molar mass — reports molarity for work that thinks in moles. The molar-mass presets match our catalog's published values exactly.
Bench math for preparing a stock solution — not guidance for use. Research use only.
- Concentration
- 5 mg/ml5,000 µg/ml
- Per 0.1 ml aliquot
- 500 µg
The math it's doing.
- Concentration (mg/ml) = peptide mass (mg) ÷ solvent volume (ml). A 10 mg vial reconstituted with 2 ml gives 5 mg/ml.
- Micrograms per 0.1 ml = concentration × 100. The same 5 mg/ml stock carries 500 µg in each 0.1 ml aliquot.
- Molarity (mol/l) = concentration (mg/ml) ÷ molar mass (g/mol). The units cancel neatly: 5 mg/ml of a 1,420 g/mol peptide like BPC-157 is 3.5 mM.
Choosing a sensible concentration.
Decide the concentration before touching the solvent, working backwards from what the experiment needs: the working concentrations your protocol calls for, the dilution steps between stock and working solution, and pipettable volumes at each step. A stock too dilute wastes vial capacity; one too concentrated forces tiny, error-prone transfers and — for aggregation-prone sequences — can exceed comfortable solubility. When in doubt, the compound's published literature is the reference for what stock concentrations its assays actually use.
Two practical notes from the storage guide worth repeating here: add solvent gently down the vial wall and dissolve by swirling, never vortexing; and if the solution will be used across multiple sessions, split it into single-use aliquots on day one rather than repeatedly drawing from one vial.
One honest caveat about the label mass.
The calculation takes the vial's peptide mass as input, and that number is only as good as the vendor's fill and content verification. Lyophilized cakes also include bound water and counter-ions — see what 99% pure actually means — so precision work should start from the batch's quantity assay on its certificate of analysis rather than the nominal label. Sentir vials are content-verified per batch, which is precisely so this arithmetic rests on a measured number.
Common questions.
Because these are research reagents, and dosing is a human-use concept. The calculator's scope — concentration and molarity for solution preparation — is the laboratory math, and deliberately nothing else.
They are the published molar masses from our product pages, e.g. ~1,420 g/mol for BPC-157 — the same values on each compound's specification table, so calculator and catalog can never disagree.
Choose “Custom molar mass” and enter the value from the compound's documentation. Concentration results don't need a molar mass at all — only molarity does.
