Research tools

Peptide concentration & volume calculator

Enter a total material amount in milligrams, the final volume of the prepared solution in millilitres, and the sample amount you want to measure. The tool reports concentration in milligrams per millilitre and the corresponding sample volume in millilitres and microlitres. It is unit arithmetic for laboratory record keeping — it does not describe a dose, a preparation method or a suitability judgement.

Inputs

Example figures

Nothing is preselected. Load a worked example to see the arithmetic, then edit any field.

Total material (mg)

The milligram amount stated on the label for the whole container.

Final solution volume (mL)

The measured volume of the finished solution. This is not assumed to equal the volume of solvent added.

Target sample amount

The amount of material you want in one sample. Choose the unit explicitly.

Syringe capacity (illustration)

Capacity changes the drawing only. It never changes the calculated concentration or sample volume.

Show a U-100 scale (100 markings per mL)

A U-100 scale divides one millilitre into 100 markings. Those markings are a volume scale only — they are not an amount of peptide and not an international unit of any compound. Capacity alone never implies a calibration: the U-100 scale is shown only when you select it here.

Result

Enter three figures to calculate.

Total material in milligrams, final solution volume in millilitres, and a target sample amount. Until all three are valid numbers greater than zero, no result is shown — the diagram stays outlined and empty.

What the arithmetic does

Concentration is total material divided by final solution volume: C = M / V. With 10 mg of material in a 2 mL final solution, the concentration is 5 mg per mL. The sample volume for a target amount is the target mass divided by that concentration: a 250 µg (0.25 mg) target at 5 mg/mL is 0.05 mL, which is 50 µL, and 5 markings on a U-100 volume scale.

Why the fields are worded this way

Total material (mg) is the amount stated for the whole container, not the amount in one sample.
Final solution volume (mL) is the volume of the finished solution. Added solvent and final volume are not the same quantity, because dissolved material occupies volume; this tool asks for the final figure and never infers it.
Target sample amount requires an explicit unit. 1 mg is 1000 µg, and switching the unit here converts the value so the physical amount you entered is preserved.

Units and scales

1 mL is 1000 µL. A U-100 scale divides one millilitre into 100 markings, so one marking is 0.01 mL or 10 µL. The term comes from insulin labelling, where U-100 means 100 insulin units per millilitre; that definition does not turn a peptide mass into an international unit. Here the markings are a volume scale only. Capacity and calibration are separate properties: selecting a 0.3, 0.5 or 1 mL capacity here changes the illustrated barrel and its labelled scale, and nothing about the calculated numbers.

Blends

For a listing that states only a combined milligram figure for two components, the arithmetic above applies to that combined figure. A per-component concentration cannot be calculated without a stated component ratio, and this tool does not assume one.

Limits

This estimates a laboratory sample volume. It does not establish a suitable dose, solvent, stability, sterility or suitability for people.
Actual device graduations vary between products. The illustration is a schematic for reading the number — it is not a physical calibration and does not represent any particular device.
No claim is made about the real capacity of any container, or about how much material is recoverable from it.
The tool contains no preparation, handling or administration instructions, and no recommended amounts.