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Laboratory tools / 01

Peptide molarity
& dilution calculator.

Work confidently across mass, volume and concentration. A free calculation workspace for laboratory research.

Read the calculation notes

Your inputs

Convert concentration

Convert mass per volume into molar concentration.

g/mol

Use the molecular weight for the same chemical form and mass basis as your material.

Label this calculation Optional

Used in your printed or copied result. It is not added to an enquiry.

The working, made visible

Understand
the numbers.

These examples use hypothetical values to explain the arithmetic. They do not specify a product, solvent or research protocol.

01 / Worked example

From mass to molarity

1 mg/mL → 1 mM

For an illustrative molecular weight of 1,000 g/mol: 1 mg/mL is 1 g/L. Dividing by 1,000 g/mol gives 0.001 mol/L, or 1 mM.

02 / Worked example

A specified solution

1 mM × 10 mL → 10 mg

With the same illustrative molecular weight, 0.001 mol/L × 0.01 L × 1,000 g/mol gives 0.01 g, or 10 mg. The volume is the final solution volume.

03 / Worked example

A stock dilution

5 mM → 50 µM

For a final volume of 10 mL, the stock volume is 0.1 mL (100 µL). Bring that aliquot to 10 mL final volume. The calculated diluent volume is 9.9 mL if volumes are additive.

Equations & unit conversions

Molar concentration is the amount of substance per litre of final solution. This calculator converts the inputs to grams, litres and mol/L before performing the calculation.

Concentration
C (mol/L) = mass concentration (g/L) ÷ MW (g/mol)
Solution preparation
m (g) = C (mol/L) × V (L) × MW (g/mol)
Stock dilution
C₁V₁ = C₂V₂

1 mM = 1,000 µM · 1 mL = 1,000 µL · 1 mg/mL = 1 g/L

Method references: R&D Systems molarity calculator and dilution calculator.

Use the right measurement basis

Match the molecular weight to the material’s chemical form and the basis of the mass entered. A parent peptide, salt or hydrated form can have a different molecular weight.

HPLC purity is not automatically the proportion of the weighed material represented by the peptide. This tool applies no assay, purity, moisture or counterion correction. Confirm the measurement basis from the relevant specification or analytical report.

Purity and content explained

For dilution, both concentrations must describe the same solute on the same basis. The calculation assumes conservation of solute. Bring the aliquot to the specified final volume; the separate diluent estimate assumes additive volumes.

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For laboratory calculations only. Results depend on the inputs and do not establish identity, purity, solubility or suitability for an application. Not for human or veterinary dosing.