Tesofensine (400 mcg, 60 units)
LABORATORY TOOLS / 01
Peptide Reconstitution
Calculator
Calculate peptide concentration and the volume to draw for your required amount. Enter net peptide content, liquid volume and a target amount to see the result in microliters.
RESEARCH USE ONLY
Clear inputs.
Traceable calculations.
Build your calculation
mg · mL · µg · µLEnter your net peptide amount and target concentration to find the final solution volume to prepare.
SOLUTION VOLUME TO ADD
Enter valid values to see your result.
SOLUTION VOLUME TO ADD
mL
Use compatible solvent to bring the dissolved peptide to this total final volume, including any liquid already present. This is not an instruction to add that full volume on top of an existing solution. Check solubility and container capacity.
1 mg = 1,000 µg1 mL = 1,000 µLCalculations run in your browser
For laboratory research only. Not for human or veterinary administration. These calculators do not recommend a peptide amount or solvent.
THE QUICK ANSWER
How do you calculate peptide draw volume?
A peptide reconstitution calculator uses three inputs, net peptide amount, solution volume, and peptide amount needed per draw, to calculate the stock concentration and volume to withdraw with a pipette. Concentration equals peptide mass divided by final solution volume. The volume to withdraw equals the peptide amount needed divided by that concentration.
01 / GET STARTED
How to use the peptide calculator
Four inputs connect the material in your vial to the amount needed for your experiment.
- 01
Enter net content
Enter the documented peptide mass in milligrams. Check the batch report for what the amount represents.
- 02
Enter liquid volume
Add all solvent volumes together. If you have measured the final solution volume, use the optional field for that value.
- 03
Set the amount needed
Enter the mass required for one transfer in µg or mg. This comes from your research method, not the calculator.
- 04
Check your pipette
Enter its maximum volume and, optionally, its minimum. Results update automatically. Check the volume against the instrument’s operating range.
02 / CHECK THE MATH
Peptide reconstitution formulas
with examples
Use consistent units and the final solution volume. 1 mg/mL = 1 µg/µL, a useful shortcut when calculating small transfers.
| Calculation | Formula | Worked example |
|---|---|---|
| Stock concentration | Net peptide mass (mg) ÷ final volume (mL) | 5 mg ÷ 2 mL = 2.5 mg/mL |
| Net peptide mass | Powder mass × documented net-content fraction | 5 mg × 0.80 = 4 mg of peptide |
| Volume for an amount needed | Required mass (µg) ÷ concentration (µg/µL) | 250 µg ÷ 2.5 µg/µL = 100 µL |
| Final volume for a target concentration1 | Net peptide mass (mg) ÷ target concentration (mg/mL) | 10 mg ÷ 2 mg/mL = 5 mL final volume |
| Molar concentration5 | [Concentration (mg/mL) ÷ molecular weight (g/mol)] × 1,000,000 | 2.5 mg/mL ÷ 1,000 g/mol × 1,000,000 = 2,500 µM |
| Stock dilution6 | C₁ × V₁ = C₂ × V₂ | 40 µL of 2.5 mg/mL stock made up to 1 mL = 0.1 mg/mL |
Net-content fraction means a documented peptide mass fraction, not HPLC purity. Molecular weight must match the mass basis. In the dilution formula, C is concentration and V is volume; use matching units on both sides.
CHECK THE MAIN CALCULATOR
5 mg in 2 mL → 2.5 mg/mL. A 250 µg draw requires 100 µL (0.1 mL).
| Net peptide amount | 1 mL final volume | 2 mL final volume | 3 mL final volume |
|---|---|---|---|
| 5 mg | 5 | 2.5 | 1.667* |
| 10 mg | 10 | 5 | 3.333* |
| 20 mg | 20 | 10 | 6.667* |
*Rounded to three decimal places. All concentrations are in mg/mL, numerically equal to µg/µL.
Arithmetic examples only. They do not establish suitable solvent volumes, concentrations or vial capacity for any particular peptide.
03 / PEPTIDE BLENDS
Calculating Concentration for Peptide Blends
Calculate each peptide separately: divide its amount in milligrams by the same final solution volume. The total blend amount tells you the combined concentration, not the concentration of each peptide.7
For example, a blend containing 10 mg of Peptide A and 5 mg of Peptide B, dissolved to a final volume of 2 mL, gives:
| Component | Amount in vial | Concentration | Amount in a 100 µL draw |
|---|---|---|---|
| Peptide A | 10 mg | 5 mg/mL | 500 µg |
| Peptide B | 5 mg | 2.5 mg/mL | 250 µg |
| Combined blend | 15 mg | 7.5 mg/mL | 750 µg total |
In the Peptide blend tab, enter 10 mg for Peptide A, 5 mg for Peptide B and 2 mL of solution. Select Peptide B and enter 250 µg as the amount needed per draw. The result is 100 µL. That same draw also contains 500 µg of Peptide A; you cannot withdraw one component without the other.
Adding more solvent lowers both concentrations but does not change their ratio. For an equal blend, such as 10 mg + 10 mg in 2 mL, each peptide is 5 mg/mL.
Use the documented amount of each component from the batch COA. A total blend weight alone is not enough to calculate individual concentrations. Examples assume complete dissolution and uniform mixing; they do not recommend a blend, solvent or experimental amount.
04 / START WITH THE RIGHT MASS
Net peptide content
is not HPLC purity
Use peptide mass in the calculator, not the weight of everything in the vial. A peptide preparation may also contain water, salts or counter-ions. HPLC purity describes a different measurement; it is not a direct measure of milligrams present.2
If your report already gives the net peptide amount in mg, enter that amount directly. Do not multiply it by the HPLC purity percentage. If the documentation only gives gross powder weight, confirm the content basis before calculating.
For a blend, calculate one component at a time using its documented mass and the shared solution volume. The total blend weight is not the amount of each peptide.
Find your batch’s certificate of analysis05 / BEFORE YOU TRANSFER
Use the meter as a volume reference.
The meter shows the calculated volume as a share of the maximum you entered. A 100 µL result fills 50% of a 200 µL scale and 10% of a 1,000 µL scale. The required volume stays 100 µL.
Capacity alone does not confirm accuracy. Check the manufacturer’s minimum volume, resolution, matching tips and performance specifications.3 A result outside that range calls for suitable equipment or a validated intermediate dilution in your laboratory workflow.
06 / USEFUL ANSWERS
Peptide calculator FAQs
How much solution should I add to a peptide vial?
There is no single amount that suits every peptide vial. The volume depends on how much peptide it contains, how readily it dissolves in the chosen solvent, and the concentration needed for your experiment. Higher-content vials—for example, 100 mg versus 5 mg of the same peptide—may need more solvent to dissolve fully. Follow the peptide-specific preparation guidance and stay within the vial’s capacity.4
Is solution added the same as final solution volume?
Not necessarily. This calculator estimates concentration from the liquid added unless you enter a measured final volume. For more precise preparation, use the total volume after dissolution, including any initial co-solvent. Do not count the same liquid twice.
How do I convert mg to mcg and mL to µL?
Multiply by 1,000 in both cases: 1 mg = 1,000 mcg and 1 mL = 1,000 µL. The symbols µg and mcg mean the same thing. For example, 250 µg is 0.25 mg, and 100 µL is 0.1 mL. The calculator handles the target amount conversion automatically.
Does changing pipette capacity change the amount needed?
No. The net peptide mass, solution volume and target amount determine the draw volume. Changing pipette capacity only changes the meter scale and the capacity check. Always use the numeric volume result when setting a suitable pipette.
Can I use the calculator for peptide blends?
Yes, for one documented component at a time. If a blend contains 5 mg of peptide A and 5 mg of peptide B, enter 5 mg when calculating an amount of A. Use the full shared solution volume. Each draw also contains peptide B in the ratio present in the solution.
Does adding more solution reduce the peptide amount?
It reduces concentration, not the total peptide mass, assuming complete dissolution and no material loss. Doubling the final volume halves the concentration, so you need twice the draw volume to obtain the same target mass.
How do I calculate molar concentration from mg/mL?
Divide concentration in mg/mL by molecular weight in g/mol, then multiply by 1,000,000 to get µM. For example, 2.5 mg/mL with a molecular weight of 1,000 g/mol is 2,500 µM (2.5 mM). Open the optional molecular-weight field under net peptide amount to see this result.5
Can this tool recommend a dose or a reconstitution solvent?
No. It converts a researcher’s chosen mass and volume inputs into a laboratory transfer volume. It does not select experimental amounts, determine solvent compatibility or provide instructions for human or veterinary administration.
Sources & calculation notes
- R&D Systems: Reconstitution Calculator. Mass, concentration and volume relationships.
- Thermo Fisher Scientific: PKI (14–22), Myristoylated — product analysis sheet. An example of HPLC purity, peptide content and net mass reported separately.
- Eppendorf: Reference 2 Pipette Performance Data Sheet. Specified operating ranges and performance.
- Sigma-Aldrich: Synthetic Peptide Handling & Storage Protocol. Peptide-specific solvent compatibility.
- R&D Systems: Molarity Calculator. Molecular weight, mass and molar concentration.
- R&D Systems: Dilution Calculator. Stock-to-final dilution relationships.
- NIST: Guide to the SI, Chapter 8. Section 8.6.5, note 1, defines a component’s mass concentration as its mass divided by the volume of the mixture.
Results are arithmetic estimates, not analytical measurements. Displayed decimal places do not establish equipment precision. The calculation assumes a completely dissolved, uniform solution and reliable input data; it does not model adsorption, degradation or transfer losses.