The formula
Concentration is fill divided by diluent.
mg/mL = labelled fill (mg) ÷ diluent volume (mL). Multiply by 1,000 for µg/mL, and divide the µg/mL figure by 10 for the mass in a 0.1 mL aliquot.
Free dilution arithmetic
Peptide reconstitution calculator: fill and diluent to mg/mL.
Enter the fill printed on the vial and the diluent volume you added. The calculator returns mg/mL, µg/mL, the mass in a 0.1 mL aliquot, and the total in the vial, or works backwards from a target concentration to the diluent volume. It is dilution arithmetic, nothing more.
No signupRuns in your browserCopyable recordResearch-use-only
Already know the concentration? Check the certificate that documents the lot.
The mass printed on the vial label, not the detected quantity on a certificate.
Volume of solvent added to the vial. The tool does not recommend a volume.
Concentration
2.5 mg/mL
2,500 µg per mL of solution
Per 0.1 mL
250 µg
Mass contained in a 0.1 mL aliquot of the solution
Total mass in vial
5,000 µg
5 mg labelled fill, before any transfer loss
Dilution factor
0.4 mL per mg
Diluent volume divided by labelled fill
Runs entirely in this browser. Nothing is submitted or saved.
This calculator performs dilution arithmetic only. It does not convert a mass into an administration volume, does not provide dosing, and does not describe any human or animal use. LynxLabs supplies research-use-only material that is not approved for human or animal use.
The usual mistake
Mixing the label with the certificate.
A certificate reports a detected quantity for one sample. Dilution starts from the labelled fill and keeps the analytical result in its own field, or the record no longer reconciles.
What it will not do
It does not produce a protocol.
No administration volumes, no dosing, no human or animal use. Research-use-only material is not approved for either, and this tool has no opinion about your protocol.
How to calculate peptide concentration, step by step
Peptide reconstitution math is one division repeated four ways. Do it in the same order every time and write the numbers into the same record as the lot and the certificate, otherwise the concentration cannot be tied back to the vial it came from.
- 1. Read the labelled fill. Use the mass on the vial, typically 2 mg, 5 mg, 10 mg, or 30 mg. If the listing offers two variants, confirm which one is in hand before calculating anything.
- 2. Record the diluent volume. Write down what you actually added, not what the label suggested. A 1 mL, 2 mL, or 3 mL addition changes the concentration by a factor of three across that range.
- 3. Divide. mg/mL = fill ÷ diluent. A 5 mg fill in 2 mL is 2.5 mg/mL; the same fill in 5 mL is 1 mg/mL.
- 4. Convert to micrograms. Multiply mg/mL by 1,000. 2.5 mg/mL is 2,500 µg/mL, so a 0.1 mL aliquot holds 250 µg.
- 5. Note the assumptions. The result is nominal. Displacement, transfer loss, and incomplete dissolution all push the real concentration below the calculated figure, so the assumption belongs in the record next to the number.
Concentration for common fills and diluent volumes
Nominal mg/mL for the fills LynxLabs lists, at three diluent volumes. Read across a row to see how much a single extra millilitre changes the number.
| Labelled fill | 1 mL diluent | 2 mL diluent | 3 mL diluent |
|---|---|---|---|
| 2 mg | 2 mg/mL 200 µg per 0.1 mL | 1 mg/mL 100 µg per 0.1 mL | 0.6667 mg/mL 66.67 µg per 0.1 mL |
| 5 mg | 5 mg/mL 500 µg per 0.1 mL | 2.5 mg/mL 250 µg per 0.1 mL | 1.667 mg/mL 166.7 µg per 0.1 mL |
| 10 mg | 10 mg/mL 1000 µg per 0.1 mL | 5 mg/mL 500 µg per 0.1 mL | 3.333 mg/mL 333.3 µg per 0.1 mL |
| 30 mg | 30 mg/mL 3000 µg per 0.1 mL | 15 mg/mL 1500 µg per 0.1 mL | 10 mg/mL 1000 µg per 0.1 mL |
Frequently asked questions
How do I calculate peptide concentration after reconstitution?
Divide the labelled fill in mg by the diluent volume in mL. A 5 mg fill with 2 mL of diluent gives 2.5 mg/mL, which is 2,500 µg/mL. Multiply mg/mL by 1,000 to get µg/mL, and divide that by 10 to get the mass in a 0.1 mL aliquot. The calculator above does all three at once.
How many mg are in a mL of reconstituted peptide?
It depends entirely on how much diluent you added. A 10 mg fill in 2 mL is 5 mg/mL; the same 10 mg fill in 5 mL is 2 mg/mL. Concentration is not a property of the peptide, it is a property of that vial and that diluent volume, so record both numbers together.
Is the labelled fill the same as the amount detected on the COA?
No. The label states a nominal fill, while a certificate reports an analytical result for one sample, such as 4.87 mg detected against a 5 mg label. Use the labelled fill for dilution arithmetic and keep the reported result as a separate documentation field, because they describe different things.
Does this calculator tell me how much to use?
No. It returns concentration and diluent volume only. It does not convert mass into an administration volume and it does not provide dosing guidance. LynxLabs supplies research-use-only material that is not approved for human or animal use.
Why does the calculated volume not match the vial exactly?
Because the arithmetic ignores displacement and transfer loss. Lyophilised powder and the peptide itself take up volume, and material stays behind in the vial and the filter. Record the diluent volume you actually added, treat the calculated concentration as nominal, and note the assumption with the record.
What diluent volume should I choose?
That is a protocol decision, not a supplier one. Work backwards instead: decide the concentration your documentation needs, then use the second mode above to get the diluent volume. Whatever you choose, keep the fill, the diluent volume, the lot, and the certificate together in the same record.