Concentration Calculator

Laboratory calculator

Equations used

Use a molar mass in g/mol for the chemical form whose mass you entered. For example, if the mass is for a salt, use the molar mass of that salt. If the form is uncertain, leave molar mass blank and use the mg/mL result. ^{[1] [2]}

Check the inputs before relying on the result

Use the measured final volume of the solution. The volume of solvent added can differ. Check what the stated mass represents using the material’s own records. The guide to product specifications and identity records explains which fields to look for. For the concentration of one peptide in a blend, use that peptide’s mass and the final volume of the whole solution. The combined mass alone cannot tell you an individual peptide’s concentration.

No automatic purity correction is applied. An HPLC area percentage is not assumed to be a target mass fraction. Read identity, purity and assay and net peptide content if the basis is uncertain.

Use the laboratory preparation guide to establish the input records. If the proposed diluent is labelled bacteriostatic water, consult its reference profile for the separate specification questions; the calculator cannot decide compatibility.

Worked check

For a fictional laboratory material, enter 12 mg and a final solution volume of 6 mL. You can check the three results by hand.

• Mass concentration. 12 mg ÷ 6 mL = 2 mg/mL.
• Amount concentration. With a matching molar mass of 600 g/mol, 0.012 g ÷ 600 g/mol = 0.000020 mol. Dividing by 0.006 L gives about 0.00333 mol/L, or 3.33 mmol/L.
• Aliquots. Seven full aliquots of 0.8 mL use 5.6 mL. That leaves 0.4 mL before transfer losses.

Use the unit conversions guide if your records use a different mass, volume or concentration unit. The calculator cannot account for pipetting uncertainty, dead volume or transfer losses. Enter the actual measurements in your research lot log.

Supporting checks