Peptide calculator: reconstitution and dilution
A laboratory calculator: from the vial content and solvent volume it works out the solution concentration, the volume to draw with a pipette in µl, the number of aliquots and the dilution of a stock solution using C1V1 = C2V2.
- Concentration
- Volume in µl
- C1V1 dilution
- Aliquots
Reconstitution and dilution calculator
Concentration after dissolving, volume to pipette and preparation of a working solution.
For example bacteriostatic water. The volume only changes the concentration, not the amount of peptide.
Amount of substance for one experiment, well or aliquot.
The lyophilisate also contains counter-ions and residual water. If the certificate of analysis states the net peptide content, enter it for an exact concentration.
You can take the value from Reconstitution mode with the “Use as stock solution” button.
The tool only converts units for laboratory work. Always double-check the results. The products are intended solely for in vitro research.
The tool only converts units for laboratory work. Always double-check the results. The products are intended solely for in vitro research.
How to use the peptide calculator
- 1
Enter the vial content
The number of milligrams of lyophilisate stated on the vial, e.g. 5 mg or 10 mg.
- 2
Choose the solvent volume
How much bacteriostatic water or other solvent you add to the powder.
- 3
Enter the desired amount
The amount of substance in µg or mg you need for one experiment or aliquot.
- 4
Read off the volume in µl
The calculator shows the volume to draw with a pipette, the concentration and the number of aliquots. In Dilution mode you can prepare a working solution.
How peptide reconstitution is calculated
Reconstitution means dissolving a lyophilized peptide in a precisely measured volume of solvent. The resulting concentration is the amount of peptide divided by the volume: 10 mg ÷ 2 ml = 5 mg/ml. The same calculation applies to every lyophilized vial, for example GHK-Cu 50 mg or KPV 5 mg.
You get the volume to draw by dividing the desired amount by the concentration. 250 µg (0.25 mg) at 5 mg/ml corresponds to 0.05 ml, i.e. 50 µl. It is useful to know that 1 mg/ml is the same as 1 µg/µl – at a concentration of 5 mg/ml, every microlitre contains 5 µg of substance.
Volumes below roughly 10 µl cannot be measured accurately with ordinary pipettes. If the calculator shows a very small volume, add more solvent or prepare a working solution by dilution. Dilution is calculated with the relationship C1 × V1 = C2 × V2: from the stock solution concentration (C1), the target concentration (C2) and the final volume (V2) you get the volume of stock solution (V1), which you then top up with solvent.
The weight on the vial states the amount of lyophilisate. Besides the peptide, this also contains counter-ions (e.g. acetate) and residual water, so the actual peptide content is usually below 100%. For precise work, enter it from the certificate of analysis – you will find the declared amount and purity of individual batches in the laboratory test results. You can read more about storing solutions in the article how to store peptides.
Worked reconstitution examples
Peptide content 100%. The numbers match the calculator above.
| Vial | Solvent | Concentration | Amount | Draw |
|---|---|---|---|---|
| 5 mg | 2 ml | 2.5 mg/ml | 250 µg | 100 µl |
| 10 mg | 2 ml | 5 mg/ml | 250 µg | 50 µl |
| 10 mg | 3 ml | 3.33 mg/ml | 500 µg | 150 µl |
| 50 mg | 5 ml | 10 mg/ml | 1 mg | 100 µl |
| Dilution 5 mg/ml → 100 µg/ml, 1 ml | C1V1 = C2V2 | 20 µl + 980 µl | ||
Unit conversions: µg, mg, ml and µl
The most common calculation mistake is mixing up micrograms and milligrams. 1 mg = 1,000 µg, 1 ml = 1,000 µl and 1 mg/ml = 1 µg/µl.
Micrograms to milligrams
| µg | mg |
|---|---|
| 100 µg | 0.1 mg |
| 250 µg | 0.25 mg |
| 500 µg | 0.5 mg |
| 1,000 µg | 1 mg |
| 2,500 µg | 2.5 mg |
Millilitres to microlitres
| ml | µl |
|---|---|
| 0.01 ml | 10 µl |
| 0.05 ml | 50 µl |
| 0.1 ml | 100 µl |
| 0.25 ml | 250 µl |
| 1 ml | 1,000 µl |
Peptide calculator FAQ
How do I calculate peptide concentration after reconstitution?
Divide the peptide content of the vial by the volume of solvent added. For example, 10 mg in 2 ml gives 5 mg/ml. If the certificate of analysis states a peptide content below 100%, first multiply the weight of the lyophilisate by it.
How much solvent should I add to a peptide vial?
Usually 1 to 3 ml. The solvent volume only changes the concentration, not the total amount of peptide. Choose it so that the volumes you will draw fall within the accurate range of your pipette – ideally above 10 µl.
How do I convert mg/ml to µg/µl?
There is nothing to convert – the units are equal. 1 mg/ml corresponds to 1 µg/µl, so at a concentration of 2.5 mg/ml every microlitre contains 2.5 µg of substance.
How do I prepare a working solution by dilution?
Use the relationship C1 × V1 = C2 × V2. For example, from a 5 mg/ml stock solution you prepare 1 ml of a 100 µg/ml solution by drawing 20 µl of stock solution and adding 980 µl of solvent. The calculator does this in C1V1 Dilution mode.
How many aliquots do I get from one vial?
Divide the peptide content by the desired amount per aliquot. A 5 mg vial gives 20 aliquots of 250 µg. Dividing the solution into aliquots limits repeated thawing and handling of the vial.
Why is the peptide content lower than the weight of the powder?
Besides the peptide itself, the lyophilisate also contains counter-ions, such as acetate or trifluoroacetate, and residual water. The net peptide content is therefore usually 70–90% of the weight. For an exact concentration, enter it into the calculator from the certificate of analysis.
Is the peptide calculator free?
Yes. The calculator is free and only converts units for laboratory work – always double-check the results.
Need a solvent for reconstitution?
Bacteriostatic water in 3 ml vials with 0.9% benzyl alcohol, tested by the Janoshik laboratory, delivered across Czechia and Slovakia in 3–5 days.
All products are intended solely for in vitro research and laboratory use. They are not intended for human consumption.