Peptide Reconstitution Calculator
Calculate stock concentration and the required laboratory aliquot from a peptide mass and solvent volume.
Calculate Peptide Concentration and Aliquot Volume
Enter a known peptide mass and solvent volume to calculate the resulting stock concentration, then enter a target experimental quantity to calculate the aliquot volume required to obtain it.
The quantity of peptide required for a single laboratory aliquot or sample.
Results update instantly as you type. This tool performs a mathematical calculation only — always independently verify results before using them in a laboratory procedure.
How This Calculator Works
Research peptides are typically supplied as a lyophilized (freeze-dried) powder because it is more stable during transport and storage than a liquid solution. Before use, the powder is reconstituted — dissolved in a solvent or diluent — to form a liquid stock solution at a known concentration. This calculator turns that mass-and-volume relationship into a concentration, then converts a target quantity into the aliquot volume needed to obtain it.
Formula and Unit Definitions
Stock concentration = peptide mass ÷ solvent volume
Required aliquot volume = target experimental quantity ÷ stock concentration
mg (milligram) and µg (microgram) are units of mass, where 1 mg = 1,000 µg. mL (millilitre) and µL (microlitre) are units of volume, where 1 mL = 1,000 µL. All values are standardized internally to a common unit before a calculation is performed, then converted back for display.
Worked Laboratory Example
Suppose a vial contains 5 mg of peptide, and 2 mL of solvent is added.
Stock concentration = 5 mg ÷ 2 mL = 2.5 mg/mL (equivalent to 2.5 µg/µL)
Target experimental quantity = 250 µg
Required aliquot volume = 250 µg ÷ 2.5 µg/µL = 100 µL (0.1 mL)
The 2 mL stock solution in this example would yield approximately 20 equal aliquots of 100 µL each. These figures are for illustration only — always calculate from your own vial mass, solvent volume and target quantity.
Accuracy and Limitations
- Input values should come from reliable documentation, such as a vial label or certificate of analysis.
- An incorrect mass, volume or unit entry will produce an incorrect concentration and aliquot volume.
- Laboratory micropipettes have practical measurement limits; a mathematically correct result may still be impractical to measure.
- This calculator does not account for peptide purity, displacement volume, degradation, handling losses, or solvent compatibility.
See the full calculation methodology for rounding rules, validation logic and everything this calculator excludes.
Frequently Asked Questions
What does the peptide reconstitution calculator calculate?
It calculates the stock concentration of a reconstituted peptide solution and the aliquot volume required to obtain a specified experimental quantity, from the peptide mass and solvent volume you enter.
Does adding more solvent change the total peptide mass?
No. Changing the solvent volume only changes the concentration of the resulting solution. The total mass of peptide in the vial stays the same regardless of how much solvent is added.
Does this calculator tell me which solvent to use?
No. It performs mathematical calculations only. Always use the solvent specified in the manufacturer’s documentation, certificate of analysis, validated protocol or institutional procedure.
Can this calculator be used for human or animal dosing?
No. This calculator is not designed for, and must not be used for, human or animal dosing. It is a mathematical tool intended for laboratory research and sample preparation only.