Benzodiazepines vary enormously in potency by weight — a milligram of alprazolam is not comparable to a milligram of diazepam. This calculator converts a dose of one benzodiazepine to a diazepam-equivalent dose, then to a dose of a different target agent, using the widely cited Ashton Manual equivalence ratios. It is intended as an educational reference for understanding relative potency, not as a tool for self-directed dose changes.
How diazepam-equivalent conversion works
Diazepam is used as the reference agent because it has been the most extensively studied benzodiazepine in withdrawal research and has a long half-life that produces a relatively smooth taper. The Ashton Manual establishes approximate doses of other benzodiazepines that produce a comparable clinical effect to 10 mg of diazepam — for example, 1 mg of lorazepam, 0.5 mg of alprazolam, or 20 mg of temazepam.
This calculator derives a per-1mg factor from each of those ratios, converts the source dose to its diazepam-equivalent, and then converts that diazepam-equivalent to the target drug's dose using the target's own factor. The math is a simple two-step ratio, but the underlying equivalence data reflects decades of clinical experience switching patients to diazepam at the start of withdrawal programs.
Why cross-tolerance and taper supervision matter
Cross-tolerance between benzodiazepines is usually substantial but rarely complete, and it can vary with the duration of use, the specific agents involved, and individual patient factors. This means the mathematically equivalent dose is a starting estimate, not a guaranteed match — clinicians often prescribe a somewhat lower dose than the strict equivalent when switching agents, to build in a margin of safety.
Abrupt discontinuation or an overly aggressive conversion between benzodiazepines carries a genuine risk of seizures, severe anxiety, and other withdrawal complications, particularly for patients who have used a benzodiazepine at a substantial dose for an extended period. Any dose change or taper must be planned and supervised by the prescribing clinician — this calculator does not generate a taper schedule and should not be used to plan one independently.
Limits and edge cases
Equivalence ratios are population averages, not individualized predictions — actual sensitivity can differ based on age, hepatic and renal function, concurrent medications, and duration of prior use. The calculator also does not adjust for route of administration (it assumes oral dosing) or for partial cross-tolerance that can develop after long-term use of a single agent.
Half-life ranges shown in the Half-Life Reference tab are population ranges for the parent compound, with wider ranges for drugs with active metabolites (diazepam, chlordiazepoxide); actual clearance varies with age and hepatic function. This tool is for clinical/educational reference only and does not replace an individualized plan from a treating clinician or pharmacist.