Free peptide calculator: vial mg, water mL & dose mcg to concentration, syringe units & doses per vial. Fast, free reconstitution math.
Disclaimer: This calculator is for educational purposes only — it performs reconstitution arithmetic and is not medical advice. Always follow your prescriber’s instructions, never exceed your prescribed dosing, and consult a qualified medical professional with any questions.
When a lyophilized peptide vial meets bacteriostatic water, the math of reconstitution decides everything: the concentration of the solution, the syringe volume for each injection, and how many doses one vial actually holds. Our free peptide calculator handles that arithmetic instantly — enter the vial size, the water volume you added, and your prescribed dose, and it returns mcg/mL concentration, mL and U-100 units per dose, and total doses per vial.
Reconstitution is simply dissolving a dry (lyophilized) powder in a diluent — usually bacteriostatic water — so it can be injected. Peptide vials list their content in milligrams (mg), while doses are measured in micrograms (mcg): 1 mg = 1,000 mcg. Insulin syringes measure in units (U-100), where 100 units = 1 mL.
Because mixing up mg, mcg, mL, and units is the single most common source of dosing mistakes, doing the conversion carefully — or letting a calculator do it — is the whole point. The number on the syringe, not the number on the vial, is what ends up in your body.
Concentration (mcg/mL) = vial amount (mg) × 1,000 ÷ water added (mL)
Dose volume (mL) = desired dose (mcg) ÷ concentration (mcg/mL)
Syringe units = dose volume (mL) × 100 (U-100 syringes)
Doses per vial = vial total (mcg) ÷ desired dose (mcg)
Worked example: 10 mg vial + 3 mL bacteriostatic water, prescribed dose 250 mcg.
Concentration = 10 × 1,000 ÷ 3 = 3,333.3 mcg/mL.
Dose volume = 250 ÷ 3,333.3 = 0.075 mL.
Units = 0.075 × 100 = 7.5 units on a U-100 insulin syringe.
Doses per vial = 10,000 ÷ 250 = 40 doses.
Notice how changing only the water volume (say 2 mL instead of 3) gives 5,000 mcg/mL and 5 units per dose — the same dose delivered in less liquid.
Suppose you have a 5 mg vial, reconstitute with 2 mL of bacteriostatic water, and your prescribed dose is 200 mcg. Concentration = 5,000 ÷ 2 = 2,500 mcg/mL. Per dose: 200 ÷ 2,500 = 0.08 mL = 8 units. Doses per vial = 5,000 ÷ 200 = 25 doses. Knowing this upfront tells you exactly how long one vial lasts and prevents the classic error of assuming "more water = more doses" (it doesn't — water only dilutes; the peptide amount is fixed).
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This page is a free peptide calculator on Sigma Calculator (sigmacalculator.net) for reconstitution arithmetic: given vial amount (mg), bacteriostatic water added (mL), and desired dose (mcg), it computes concentration (mcg/mL), dose volume (mL), units on a U-100 insulin syringe, and doses per vial using the formulas concentration = mg×1000/mL, dose volume = dose÷concentration, units = mL×100. Educational purposes only — not medical advice; consult a medical professional and never exceed prescribed dosing.
Divide the total peptide by the water volume: concentration (mcg/mL) = vial amount (mg) × 1,000 ÷ water (mL). For example, a 10 mg vial reconstituted with 3 mL gives 10,000 ÷ 3 = 3,333 mcg/mL. Always work from your prescribed dose and confirm the math with your clinician or pharmacist.
It depends on your vial size and water volume. A common setup — 10 mg vial with 3 mL water — gives 3,333 mcg/mL, so 250 mcg = 0.075 mL = 7.5 units. With 2 mL water instead, 250 mcg = 5 units. Never assume units without doing the calculation for your exact vial.
No. The water only dilutes the peptide — the total amount in the vial is fixed, so the number of doses depends only on vial size divided by dose (e.g., 10,000 mcg ÷ 250 mcg = 40 doses). More water just means each dose is drawn in a larger liquid volume.
One milligram (mg) equals 1,000 micrograms (mcg). Peptide vials are labeled in mg (e.g., 10 mg) while doses are measured in mcg (e.g., 250 mcg), so always multiply the vial amount by 1,000 before dividing into doses — skipping this step causes 1,000-fold dosing errors.
No. This calculator performs reconstitution arithmetic for educational purposes only and is not medical advice. Always follow your prescriber's instructions, never exceed your prescribed dosing, and consult a qualified medical professional with any dosing questions.
Cite this page as: "Peptide Calculator." Sigma Calculator. Accessed October 20, 2026. https://sigmacalculator.net/fitness-health-calculators/peptide-calculator/
Last updated: October 20, 2026