Peptide & GLP-1 calculators — free, on the web.
Halflife Labs provides free educational calculators for peptide reconstitution (bacteriostatic water and syringe units), pharmacokinetic half-life modeling, GLP-1 dose escalation schedules, subcutaneous injection site rotation, and multi-compound stack planning. All tools use citation-backed half-life data from our compound database. These calculators are for reference only — not medical advice.
Peptide Reconstitution Calculator
Calculate syringe units, mL to draw, concentration (mg/mL), and remaining doses from vial size and BAC water volume.
Open calculator →Half-Life & Decay Simulator
Visual concentration curve, accumulation, steady-state timing, and injection overlap for 44+ compounds.
Open calculator →GLP-1 Dose Escalation Calculator
Week-by-week tirzepatide, semaglutide, and retatrutide titration schedules from FDA label steps.
Open calculator →Injection Site Rotation Tracker
Rotation schedules, site cooldown recommendations, and injection history (saved in your browser).
Open tracker →Peptide Stack Planner
Protocol overlap, injection schedule conflicts, and estimated concentration overlap across compounds.
Open planner →Compound Database
45 compounds with citation-backed half-life values, mechanisms, and pharmacokinetic reference pages.
Browse database →