Frequently Asked Questions
Short answers for beginners, grouped by topic. These pages explain the mathematics only and are not medical advice.
Using the calculator
It does arithmetic on values you enter: the concentration of a solution, the volume that contains a target amount, the matching syringe units, and how many portions a vial holds. It does not know what any substance is for.
No. Every calculator works immediately, with no sign-up.
Calculations run in your browser and the values are not sent to our server. If you press Share link, the values are placed in the page address so that others can open the same result.
Yes. Presets are only shortcuts. You can always type any value you like.
No. It only converts and divides the numbers you give it. It does not recommend doses or protocols. Decisions about any substance belong with a qualified professional and the product’s own documentation.
The input is likely empty, zero, negative or not a number. Other common causes: the target amount is larger than the whole vial, or the volume you need is more than the selected syringe can hold. Fix the highlighted value and the result appears again.
Units and conversions
1 mg = 1000 mcg. To go from mg to mcg multiply by 1000; to go from mcg to mg divide by 1000. Use the mg to mcg converter or the mcg to mg converter.
Both measure concentration. 1 mg/mL equals 1000 mcg/mL, so the same solution can be written either way. Always check which unit a number is in.
A U-100 syringe has 100 units in each 1 mL, so 1 unit is 0.01 mL. Units = mL × 100.
0.1 mL × 100 = 10 units on a U-100 syringe. The syringe units calculator converts any value.
0.3 mL (30 units), 0.5 mL (50 units) and 1.0 mL (100 units). If the volume is larger than the syringe, the calculator tells you.
Mixing up mg and mcg. That changes a number by a factor of 1000. Read the unit label next to every value before you calculate.
Reconstitution and dilution maths
It means dissolving a known amount of powder in a known volume of liquid. The key formula is concentration = amount ÷ volume. For example, 5 mg in 2 mL is 2.5 mg/mL.
No. The total amount stays the same and the concentration goes down. 5 mg in 2 mL is 2.5 mg/mL, but 5 mg in 4 mL is 1.25 mg/mL.
Volume = target amount ÷ concentration. With 2500 mcg/mL, a 250 mcg target is 250 ÷ 2500 = 0.1 mL.
Vial amount ÷ target amount, rounded down to a whole number. Any amount left over is shown as the remainder.
No. It assumes the final volume equals the volume of liquid you enter. For most everyday numbers the difference is small, but it is an assumption.
It uses C1 × V1 = C2 × V2. Fill in three values and leave one empty to solve for it. The final concentration cannot be higher than the stock concentration. See the dilution calculator.
Scientific calculations
Add the masses of each amino acid residue in the sequence, then add one water molecule. Optional terminal changes such as acetylation or amidation adjust the total. Try the molecular weight calculator.
Average mass uses the average atomic weights of each element. Monoisotopic mass uses the most abundant isotope of each element and is the value mass spectrometers usually report.
Purity is the share of the peptide material that is the target sequence, usually measured by HPLC. Assay (net peptide content) is the share of the whole powder that is peptide, with the rest being water and salts. They are different percentages.
The gross weight includes water and counter-ions. To estimate the actual peptide, multiply by assay and purity. See the peptide content calculator.
Technical questions
The formulas are exact, and results are rounded only to remove tiny computer rounding artefacts. Always double-check inputs and read the formula shown on each page.
Yes. The calculators are built for small screens and need JavaScript turned on in a current browser.
Use the contact page and include the calculator, the values you entered and what you expected.
Mathematical calculation only. Not medical advice.