Laboratory reference tool
Reconstitution & molarity calculator
Work out the concentration of a stock solution prepared from lyophilised material, or the volume of diluent required to reach a target concentration. Results are expressed as concentration and volume only.
Resulting concentration
Enter the mass in the vial and the volume of diluent added.
Stock concentration
— mg/mL
Diluent volume required
Enter the mass in the vial and the stock concentration you want to prepare.
Diluent to add
— mL
How these figures are calculated
Concentration is mass divided by volume. Adding V millilitres of diluent to m milligrams of lyophilised material gives:
C (mg/mL) = m (mg) ÷ V (mL)
Because 1 mg/mL is numerically equal to 1 µg/µL, the same figure can be read in either unit without conversion.
Where a molecular weight is supplied, molar concentration follows from the substance amount:
n (mol) = m (g) ÷ M (g/mol) c (mol/L) = n (mol) ÷ V (L)
Working in the other direction, the diluent volume needed to reach a target concentration is:
V (mL) = m (mg) ÷ C₃ (mg/mL)
These are standard solution-preparation relationships and assume the lyophilised material dissolves completely, that the solid contributes negligible volume, and that the stated mass is the mass actually present in the vial. For material of known purity, the mass of the compound itself is lower than the gross fill mass in proportion to that purity; where this matters to an experiment, substitute the corrected mass.
Important information
This tool performs arithmetic only. It converts between mass, volume and concentration. It does not recommend, suggest or calculate an amount of any substance to be administered to a human or an animal, and it must not be used for that purpose.
All products supplied by Elite Bio Labs are for laboratory research use only. They are not medicines, they are not licensed by the MHRA or any other regulator, and they are not for human or veterinary use, ingestion, injection, cosmetic use, or any diagnostic, therapeutic, prophylactic or in-vivo application. Nothing on this page should be read as encouraging or facilitating any such use.
No warranty is given. The figures returned are provided for general reference and convenience. Responsibility for verifying any calculation, for the suitability of a preparation for a given experiment, and for compliance with all applicable laws, institutional policies and safety requirements rests entirely with the user. Elite Bio Labs accepts no liability for any loss or damage arising from reliance on this tool.
Handle material in accordance with its safety data sheet. Hazard identification, handling, storage and disposal guidance for every product is published in our SDS library, and the certificate of analysis for each batch is published against the lot number printed on the vial.