How does a peptide reconstitution calculator work?

It divides the peptide in the vial (mg) by the liquid you added (mL) to get the concentration in mg/mL, divides the amount you enter by that concentration to get mL, then multiplies mL by 100 to get units on a U-100 insulin syringe.

Does the calculator tell me how much to take?

No. It only does arithmetic on numbers you enter. The amount and the volume of diluent come from your prescriber, pharmacy instructions or the product label.

Does the amount of BAC water change the dose?

Not the amount of peptide in the vial. More water makes a weaker concentration, so the same amount takes more units to draw; less water makes a stronger concentration and fewer units.

Which syringes does it support?

U-100 syringes in 0.3 mL (30 units), 0.5 mL (50 units) and 1 mL (100 units) sizes, plus U-50 and U-40 scales. Pick the one printed on your syringe box; the units and the syringe picture change to match, and you'll see a warning if the amount is more than that syringe holds.

How many full draws are in my vial?

The calculator divides the vial's mg by the amount you enter and shows the whole number of draws plus what's left over in mg and mL. Real vials give slightly less, because a little liquid stays in the vial and the needle.

Why do different calculators give different answers?

Usually because of the syringe scale (U-100 vs U-50 or U-40), rounding (some round to the nearest unit or half unit), whether they use the water you added or the final volume, and whether the vial's label amount matches its net peptide content. Check that you entered the same numbers and syringe before comparing.

Is anything I type saved or sent?

Nothing you type is sent to us. The math runs in your browser. Your last setup is saved in this browser's storage so it's there next time, and the page address updates so you can copy a link to the same setup; Clear removes both. Analytics record only that the calculator was viewed, used or copied and whether its button was clicked, never the numbers or results.

Peptide reconstitution calculator

Turn the numbers on your vial and syringe into concentration, draw volume, syringe units and full draws per vial. Runs in your browser; nothing you type is sent to us.

← All toolsUpdated October 17, 2026

A peptide reconstitution calculator turns the mg in a vial and the mL of liquid added into a concentration (mg/mL), then converts an amount you enter into mL and units on your insulin syringe.

Reconstitution calculator

Enter the numbers from your own vial, and pick the syringe in your hand. Check the U- number and size printed on the syringe box.

Concentration

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Draw volume

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Syringe units

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U-100 1 mL, holds 100

Draws in the vial

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1Concentration: vial mg mg ÷ mL added mL = concentration
2Draw volume: amount in mg ÷ concentration = draw mL
3Syringe units: draw mL × 100 units per mL (U-100) = units

Math only, not dosing advice. Follow your prescriber or label. Real vials give slightly less than the full-draw count: a little liquid stays in the vial and needle. Your last setup is saved in this browser only; Clear removes it.

Save your vial in Caliper and it remembers the concentration and use-by date you entered, alongside your dose log. The calculator above is a browser tool and is not part of the app.

Save my vial in Caliper

How the math works

Reconstitution is one formula applied twice, plus the syringe scale:

Concentration (mg/mL) = peptide in the vial (mg) ÷ liquid added (mL)
Draw volume (mL) = amount (mg) ÷ concentration (mg/mL)
Syringe units = draw volume (mL) × the syringe's units per mL (100 on U-100, 50 on U-50, 40 on U-40)

The numbered steps under the calculator run this same math with your own numbers as you type. Fields start empty on purpose: Caliper never suggests an amount.

Example 1 (made-up numbers)

A 10 mg vial with 2 mL added is 10 ÷ 2 = 5 mg/mL. An amount of 0.5 mg is 0.5 ÷ 5 = 0.1 mL, which is 10 units on a U-100 syringe. The vial holds 10 ÷ 0.5 = 20 full draws of that amount, with nothing left over on paper.

Example 2 (made-up numbers, mcg and a different scale)

A 5 mg vial with 2.5 mL added is 5 ÷ 2.5 = 2 mg/mL. An amount of 300 mcg is 0.3 mg, so 0.3 ÷ 2 = 0.15 mL. On a U-100 syringe that's 0.15 × 100 = 15 units; on a U-40 scale the same 0.15 mL is 0.15 × 40 = 6 units. The volume is identical; only the printed numbers differ. The vial holds 5 ÷ 0.3 = 16 full draws, with 0.2 mg (0.1 mL) left over.

Why do calculators give different answers?

If two calculators disagree, it's almost always one of these, not a math error:

Syringe scale. Units only mean something with a scale. 10 units on a U-100 syringe is 0.1 mL; 10 units on a U-40 scale is 0.25 mL. A 0.3 mL or 0.5 mL insulin syringe is usually still U-100, just shorter. Pick the syringe printed on your box.
Rounding. Some tools round to the nearest whole or half unit, others show decimals. We show one decimal place in units and three in mL, so 12.5 units may appear as 13 elsewhere. Real syringe markings set how precisely you can actually draw.
Water volume. Most calculators, this one included, use the liquid you added. Dissolved powder adds a tiny bit of volume, and a few tools ask for the final volume instead, which shifts the result slightly.
Net vs label content.A vial labeled 10 mg may contain a different net amount of peptide, which a lab report (COA) can show. If you enter the COA's figure in one tool and the label's in another, the concentration differs in proportion.

Calculators by vial size

Pages with a ready-made concentration table for 1, 2 and 3 mL and the calculator with the vial size filled in:

Calculators by compound

The same calculator set to a compound's label vial sizes, with a concentration table and mixing and storage notes. Pages for FDA-approved products also quote the official label dosing for the branded product. See all 31 compounds.

GLP-1 and incretin compounds

Recovery peptides

Growth hormone axis

Longevity and mitochondrial

Cognitive and sleep

Other

Two checks before you trust a result: confirm the vial strength on the label (and, for research products, what the lab report says about net content), and confirm the U- number and size on your syringe. To convert units you've already drawn back into mg, use the units-to-mg converter.

FAQ

How does a peptide reconstitution calculator work?: It divides the peptide in the vial (mg) by the liquid you added (mL) to get the concentration in mg/mL, divides the amount you enter by that concentration to get mL, then multiplies mL by 100 to get units on a U-100 insulin syringe.
Does the calculator tell me how much to take?: No. It only does arithmetic on numbers you enter. The amount and the volume of diluent come from your prescriber, pharmacy instructions or the product label.
Does the amount of BAC water change the dose?: Not the amount of peptide in the vial. More water makes a weaker concentration, so the same amount takes more units to draw; less water makes a stronger concentration and fewer units.
Which syringes does it support?: U-100 syringes in 0.3 mL (30 units), 0.5 mL (50 units) and 1 mL (100 units) sizes, plus U-50 and U-40 scales. Pick the one printed on your syringe box; the units and the syringe picture change to match, and you'll see a warning if the amount is more than that syringe holds.
How many full draws are in my vial?: The calculator divides the vial's mg by the amount you enter and shows the whole number of draws plus what's left over in mg and mL. Real vials give slightly less, because a little liquid stays in the vial and the needle.
Why do different calculators give different answers?: Usually because of the syringe scale (U-100 vs U-50 or U-40), rounding (some round to the nearest unit or half unit), whether they use the water you added or the final volume, and whether the vial's label amount matches its net peptide content. Check that you entered the same numbers and syringe before comparing.
Is anything I type saved or sent?: Nothing you type is sent to us. The math runs in your browser. Your last setup is saved in this browser's storage so it's there next time, and the page address updates so you can copy a link to the same setup; Clear removes both. Analytics record only that the calculator was viewed, used or copied and whether its button was clicked, never the numbers or results.

Related guides

For adults 18+. Educational math only, not medical advice. This tool does not recommend any dose, dilution, syringe or compound. Always follow your prescriber's instructions and the product label, and ask a pharmacist if a number doesn't look right.