How much solvent do I add to reach a target concentration?
Volume = amount of powder ÷ target concentration. Worked example: 2 µg of a lyophilized protein reconstituted at 10 µg/mL needs 0.2 mL. For a molar target, the calculator multiplies by the molecular weight first: 1 mg of a 500 g/mol compound at 10 mM is 1 mg ÷ (0.010 mol/L x 500 g/mol) = 0.2 mL.
If the certificate gives a net content or purity below 100%, enter it and the calculator uses only the active amount. The result assumes the powder's own volume is negligible, which is true for small amounts.
How do you reconstitute a lyophilized protein?
Follow the supplier's datasheet for the solvent or buffer. Spin the vial briefly so the powder is at the bottom before opening, add the solvent, and swirl or pipette gently rather than vortexing, which can denature proteins. Split the stock into single-use aliquots to avoid repeated freeze-thaw cycles; enter an aliquot size to see how many you will get.
Next steps
To dilute the stock to a working concentration, use the Dilution Calculator. For antibodies specifically, the Antibody Dilution Calculator handles 1:X ratios.
Frequently asked questions
How do I calculate the reconstitution volume?
Divide the amount of powder by the concentration you want. 1 mg at 1 mg/mL needs 1 mL; at 0.5 mg/mL it needs 2 mL.
How do I make a molar stock from a vial of known mass?
Enter the mass, the target molar concentration and the molecular weight. The calculator converts the target to mg/mL and returns the volume.
Should I vortex when reconstituting a protein?
Usually not. Swirl or pipette gently to avoid foaming and denaturing the protein, and follow the supplier's instructions.
What is net peptide content?
The fraction of a lyophilized peptide's weight that is the peptide itself, after counter-ions and water. Enter it as the content percentage to correct the volume.
Can I use this for dosing?
No. This calculator is for preparing laboratory reagent stocks for research. It does not provide dosing information for people or animals.
Is anything I enter saved or sent?
No. The calculator runs in your browser. Nothing you type is saved, sent to BioBridgeX or added to the page address, and analytics never see your numbers.
Related free tools
- Molarity Calculator: Mass to weigh, volume to add or molar concentration from the molecular weight, with units and steps.
- Dilution Calculator: C1V1 = C2V2 for any unknown, with stock and diluent volumes and the dilution factor.
- Antibody Dilution Calculator: Antibody and buffer volumes from a 1:X ratio or a stock and working concentration.
- All lab calculators and every free tool on BioBridgeX.
Sources
Check every result before use. Formulas assume ideal conditions; follow your validated lab procedures and the reagent supplier's instructions. Facts on this page last checked 27 October 2026.
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