HLCalc

HLCalc is a drug half-life and serum-level modelling app for research and education. Enter a drug library and a dosing schedule, and HLCalc plots how the amount (or concentration) of each drug in the body is predicted to build up and wash out over weeks or months.

Open the web app ↗   An Android app is on its way to Google Play.

Please read first

HLCalc is a research and educational modelling tool. It is not a prescribing aid, not a clinical decision-support system, and not a medical device. It never recommends doses and must not be used to make or inform clinical dosing decisions.

• Output comes from a deliberately simple one-compartment, first-order model using typical population values. Real pharmacokinetics vary widely between people and the model ignores active metabolites, non-linear kinetics and multi-compartment distribution.
• The bundled drug data is unverified. Check every value against the current SmPC / BNF or another authoritative source before relying on it for anything.
• Some seeded compounds are not authorised medicines and are included for kinetic modelling only.
• Do not enter patient-identifiable information.

What it does

• Drug library — seeded entries plus your own, each with half-life (and optional range, volume of distribution, bioavailability, absorption rate and therapeutic range). Seeded entries are flagged Unverified until you record a source.
• Prescriptions — dose, frequency (from four times a day to every 12 weeks, or a custom interval), duration, optional body weight, and an optional half-life multiplier for "what if the half-life were longer?" scenarios.
• Graphs — per-drug charts or an overlay, in concentration, amount in body, % of steady-state peak or % of therapeutic range, with washout, zoom, and per-drug statistics such as time to steady state and accumulation ratio.
• Honest about gaps — a banner lists unverified drugs and anything the model had to assume.
• Export — graphs as PNG, series as CSV, everything as a JSON backup.

Private by design

Everything stays on your device. There are no accounts, no analytics and no network calls from the app once it has loaded.