Free public tool
Reconstitution Calculator
Performs the arithmetic of reconstitution only: concentration from vial amount and diluent volume, then the draw volume for a dose your licensed clinician prescribed. It never generates, suggests, or adjusts a dose.
Purpose & limitations
Arithmetic is not clinical judgment. Compound stability, diluent choice, storage, sterility, and the dose itself are decisions for your prescriber and pharmacist. If any output conflicts with their instructions, follow the clinician — and tell them.
Inputs & validated ranges
| Input | Unit | Accepted range |
|---|---|---|
| Amount in vial | mg | 0.1–100 |
| Diluent volume added | mL | 0.5–10 |
| Dose prescribed by your licensed clinician | mcg | 1–20000 |
Formula & methodology
Concentration (mg/mL) = vial amount ÷ diluent volume. Draw volume (mL) = prescribed dose ÷ concentration. U-100 syringe units = draw volume × 100. Doses per vial = vial contents ÷ prescribed dose, rounded down.
Worked example
A 5 mg vial reconstituted with 2 mL: concentration = 2.5 mg/mL (2500 mcg/mL). For a clinician-prescribed 250 mcg dose: 250 ÷ 2500 = 0.1 mL = 10 units on a U-100 syringe. 20 full doses per vial.
References
- US Food and Drug Administration (2023). Certain bulk drug substances for use in compounding that may present significant safety risks. FDA Human Drug Compounding. SourceAgency notice
- US Pharmacopeia (2023). General Chapter <797> Pharmaceutical Compounding — Sterile Preparations. USP-NF. SourceStandard
Found an error in this tool’s math or documentation? Report a correction — arithmetic issues are triaged within one business day.