Benzodiazepine Conversion Calculator — Diazepam Equivalents
Convert a benzodiazepine dose from one drug to the pharmacologically equivalent dose of another using diazepam as the common reference currency.
Source drug
mg
Target drug
Approximate Lorazepam (Ativan) dose equivalent to 10.0 mg diazepam
- 1
Source potency factor (5 ÷ source equiv)
5 ÷ 5 = 1How many diazepam reference units each milligram of the source drug represents. - 2
Diazepam equivalent
10 × 1 = 10 - 3
Equivalent dose (target drug)
10 × 1 ÷ 5 = 2
How does this calculator work?
Benzodiazepine conversion: divide the source dose by the source drug's diazepam equivalency and multiply by the target drug's equivalency. Example: 1 mg lorazepam = 5 mg diazepam = 10 mg temazepam (Ashton Manual). Equivalencies are approximate; clinical dose switching requires professional supervision.
Formula
How this is calculated
Different benzodiazepines vary enormously in potency — 0.5 mg of alprazolam or clonazepam produces roughly the same effect as 5 mg of diazepam, while 25 mg of chlordiazepoxide produces a similar effect. Diazepam (5 mg) is used as the reference unit, and each drug is assigned an "equivalent dose" — the number of milligrams of that drug that matches 5 mg diazepam in pharmacological activity.
To convert: divide the source dose by the source drug's equivalent-to-5 mg ratio to obtain the diazepam equivalent, then multiply by the target drug's ratio. Equivalencies in this calculator use the Ashton Manual (Professor Heather Ashton, 2002, revised 2011) — one of the most widely cited references for clinical benzodiazepine management.
Critical limitations: equivalency tables are population averages from clinical observations, not pharmacokinetically derived constants. Individual response varies substantially based on age, hepatic function, prior tolerance, half-life differences and the presence of active metabolites. Cross-tolerances between benzodiazepines are imperfect. These figures must never be applied directly to patient care without clinical judgment from a prescribing clinician or pharmacist.
Frequently asked questions
Alprazolam is roughly 10× more potent by weight than diazepam. Its high affinity for the GABA-A receptor means a small milligram amount produces the same sedative/anxiolytic effect as a much larger diazepam dose. This high potency and its short half-life make it particularly associated with physical dependence.
They are a starting point only. Clinical switching protocols typically reduce the calculated equivalent dose by 10–25% to account for incomplete cross-tolerance, then adjust based on patient response. Slow tapering schedules (e.g., 5–10% per fortnight) are typically used to minimise withdrawal — always under direct medical supervision.
The Ashton Manual ("Benzodiazepines: How They Work and How to Withdraw", 2002, rev. 2011) by Professor Heather Ashton (University of Newcastle) is a widely used clinical guide for managing benzodiazepine dependence and withdrawal. It is the primary source for the equivalency table used here.
Also known as
TG we-Calculate Editorial Team. (2026). Benzodiazepine Conversion Calculator — Diazepam Equivalents [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/benzodiazepine-conversion-calculator
TG we-Calculate Editorial Team. "Benzodiazepine Conversion Calculator — Diazepam Equivalents." TG we-Calculate. 2026. https://we-calculate.com/calculator/benzodiazepine-conversion-calculator.
TG we-Calculate Editorial Team, "Benzodiazepine Conversion Calculator — Diazepam Equivalents," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/benzodiazepine-conversion-calculator
@misc{wecalculate_benzodiazepine_conversion_calculator, title = {Benzodiazepine Conversion Calculator — Diazepam Equivalents}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/benzodiazepine-conversion-calculator}}, year = {2026}, note = {TG we-Calculate} }
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