Benzodiazepine Conversion Calculator

Benzodiazepines share a mechanism of action (GABA-A receptor positive allosteric modulation) but differ enormously in potency, half-life, and clinical indication. Moving a patient from alprazolam to diazepam for a taper, or verifying that two prescriptions from different providers are not duplicating benzodiazepine coverage — these clinical calculations require standardized equivalency tables, which this calculator implements. The calculator uses published diazepam equivalent doses as the common denominator for any inter-agent conversion.

Diazepam Equivalent Doses: Reference Table

The following doses of each benzodiazepine are approximately equivalent to 10 mg diazepam (Valium), the reference compound:

• Alprazolam (Xanax): 0.5 mg ≈ 10 mg diazepam (ratio 1:20; alprazolam is 20× more potent than diazepam on a mg basis)
• Clonazepam (Klonopin): 0.5 mg ≈ 10 mg diazepam (ratio 1:20)
• Lorazepam (Ativan): 1 mg ≈ 10 mg diazepam (ratio 1:10)
• Oxazepam (Serax): 20 mg ≈ 10 mg diazepam (ratio 2:1)
• Temazepam (Restoril): 20 mg ≈ 10 mg diazepam (ratio 2:1)
• Triazolam (Halcion): 0.25 mg ≈ 10 mg diazepam (ratio 1:40)
• Chlordiazepoxide (Librium): 25 mg ≈ 10 mg diazepam (ratio 2.5:1)

Use this online calculator for any inter-benzodiazepine conversion. The day supply calculator and prescription calculators provide complementary medication management tools.

Why Equivalency Tables Are Approximations

Benzodiazepine equivalency tables are developed from population-level pharmacological data and represent central estimates with substantial individual variation. Key sources of deviation from tabulated equivalencies:

• Pharmacokinetic variation: CYP3A4 polymorphisms alter alprazolam and triazolam metabolism by 2–3-fold between individuals; age-related hepatic changes significantly affect diazepam's long active metabolites
• Active metabolites: diazepam, chlordiazepoxide, and clorazepate generate active metabolites (desmethyldiazepam, t₁/₂ = 36–200 hours) that substantially extend clinical effect beyond the parent drug's half-life
• Cross-tolerance: the degree of tolerance developed to one benzodiazepine only partially transfers to another, particularly at high doses — cross-taper doses often need titration above the calculated equivalency

Clinical Applications: Tapering and Cross-Tapering

The most common clinical application of benzodiazepine equivalency is planned discontinuation (tapering). The Ashton Protocol recommends converting short-acting, high-potency benzodiazepines (alprazolam, lorazepam) to equivalent doses of long-acting diazepam before initiating a gradual taper — because diazepam's long half-life and slow accumulation of active metabolites creates a smoother, more predictable pharmacokinetic profile that reduces inter-dose withdrawal symptoms. A patient stable on 4 mg alprazolam daily converts to: 4 mg alprazolam × (10 mg diazepam / 0.5 mg alprazolam) = 80 mg diazepam equivalent — a very high initial diazepam dose requiring careful conversion in divided doses with clinical supervision. This type of conversion must never be implemented without direct physician oversight and inpatient monitoring if doses are high.

Tolerance, Dependence, and Deprescribing

Physical dependence on benzodiazepines develops within 4–6 weeks of daily use at therapeutic doses; tolerance to hypnotic and anxiolytic effects often develops within 2–4 weeks. Clinical guidelines (NICE, APA, SAMHSA) recommend limiting benzodiazepine prescription to 2–4 weeks for insomnia and acute anxiety, with clear discussion of dependence risk at initiation. For patients already physically dependent, abrupt discontinuation carries serious risks including withdrawal seizures (particularly from high-dose, long-duration use) — making any conversion or taper plan a clinical decision requiring physician involvement, not a calculation tool decision.