Benzodiazepine Conversion Calculator
Select your source benzodiazepine and enter the dose, then choose the target drug to see the equipotent equivalent dose. Conversions pivot through the standard diazepam 10 mg reference unit. Results include the diazepam-equivalent, the target dose, and pharmacokinetic context for both drugs. For clinical use only with qualified supervision.
How benzodiazepine conversion works
Benzodiazepines differ widely in potency, meaning the dose required to produce a given clinical effect varies enormously from drug to drug. A conversion calculator uses a pivot reference - most commonly 10 mg of diazepam (Valium) - to express every drug in a common unit. To convert drug A to drug B, you first find how many mg of drug A equal 10 mg diazepam, then scale up or down to find the corresponding dose of drug B that equals the same 10 mg pivot. For example, alprazolam (Xanax) has an equivalence factor of 0.5 mg per 10 mg diazepam, meaning it is 20 times more potent by weight. Chlordiazepoxide (Librium) has a factor of 25 mg, making it weaker. These ratios, combined with the user's actual dose, drive the calculation.
Duration matters as much as dose
Beyond the dose, pharmacokinetics shape the clinical experience of a conversion. Short-duration benzodiazepines (triazolam, midazolam) have half-lives of a few hours and carry higher interdose withdrawal risk. Long-duration drugs (diazepam, clonazepam, chlordiazepoxide) with half-lives of 20-100 hours are smoother in steady-state and are frequently preferred for tapering protocols precisely because plasma levels fall slowly, reducing rebound anxiety and withdrawal severity. When switching from a short-acting to a long-acting benzodiazepine, clinicians typically introduce the longer-acting drug conservatively (50-75% of the calculated equivalent dose) and titrate up over several days, watching for both under-sedation and over-sedation.
Clinical context for benzodiazepine conversions
The most common clinical reasons to convert between benzodiazepines include: tapering from a short-acting drug to a longer-acting one to ease discontinuation, switching when a patient develops tolerance or side effects, and formulation changes such as moving from an oral to an IV drug in a hospital setting. The Ashton Manual (2002) is the most widely cited reference for equivalence in the context of tapering and withdrawal management. MDCalc and ClinCalc both publish similar tables grounded in the same expert-consensus literature. Note that no conversion chart has been validated in a randomized controlled trial; all factors reflect expert opinion and observational data. Hepatic impairment, advanced age, concurrent opioids or CNS depressants, and genetic variability in CYP2C19 can all shift effective potency substantially.
Special cases: midazolam and oxazepam
Midazolam deserves particular attention because its oral and intravenous forms have very different effective doses. IV midazolam reaches near-complete bioavailability, while the oral form has only about 40% bioavailability (range 35-75%), so the oral dose needed for an equivalent effect is roughly 3 times the IV dose. This calculator treats them as separate entries. Oxazepam (Serax) is often chosen for patients with hepatic disease or in elderly patients because it is conjugated directly by glucuronidation rather than by hepatic CYP enzymes and has no active metabolites, making accumulation less likely. Its slow onset (2-4 hours) means it has a low abuse potential relative to faster-acting agents.
Benzodiazepine equivalence reference table
| Drug (brand name) | Dose equiv. to 10 mg diazepam | Half-life (approx) | Duration | Onset |
|---|---|---|---|---|
| Alprazolam (Xanax) | 0.5 mg | 6-27 h | Intermediate | Fast (15-30 min) |
| Bromazepam (Lexotan) | 6 mg | 10-20 h | Intermediate | Intermediate |
| Chlordiazepoxide (Librium) | 25 mg | 5-30 h (active metabolites 36-200 h) | Long | Intermediate |
| Clonazepam (Klonopin) | 0.5 mg | 18-50 h | Long | Intermediate (30-60 min) |
| Clorazepate (Tranxene) | 15 mg | Prodrug; metabolite 36-200 h | Long | Fast |
| Diazepam (Valium) | 10 mg | 20-100 h | Long | Fast (15-30 min) |
| Estazolam (ProSom) | 1 mg | 10-24 h | Intermediate | Fast |
| Flurazepam (Dalmane) | 30 mg | Active metabolite 47-100 h | Long | Fast |
| Lorazepam (Ativan) | 1 mg | 10-20 h | Intermediate | Intermediate (30-60 min) |
| Midazolam IV (Versed) | 2.5 mg | 1-4 h | Short | Very fast (< 5 min IV) |
| Midazolam PO (Versed) | 7.5 mg | 1-4 h | Short | Fast (20-30 min) |
| Oxazepam (Serax) | 30 mg | 4-15 h | Intermediate | Slow (2-4 h) |
| Temazepam (Restoril) | 20 mg | 8-22 h | Intermediate | Intermediate (30-60 min) |
| Triazolam (Halcion) | 0.25 mg | 1.5-5.5 h | Short | Fast (15-30 min) |
| Quazepam (Doral) | 20 mg | 15-120 h | Long | Fast |
Approximate doses considered equivalent to 10 mg of diazepam (Valium). Based on the Ashton Manual and published clinical references. Use for guidance only.
Frequently asked questions
What does "diazepam equivalent" mean?
Diazepam 10 mg is used as a reference standard to which all other benzodiazepines are compared. If your dose of another drug equals, say, 20 mg of diazepam in clinical effect, that drug has a diazepam equivalent of 20 mg. It is a common way for clinicians to compare benzodiazepines on a single scale regardless of their chemical potency per milligram.
Why do the equivalence factors vary so much between drugs?
Benzodiazepines differ in their affinity for GABA-A receptor subunits, in how efficiently they are absorbed, and in how quickly they are metabolised. Triazolam (Halcion) binds the receptor very tightly and is active at 0.25 mg, while chlordiazepoxide (Librium) needs 25 mg to produce a similar effect. The "equivalence factor" captures this spread by anchoring everything to the reference 10 mg diazepam dose.
Can I use this to plan my own taper?
This calculator provides an estimate for educational and reference purposes only. Planning a taper is a medical decision that requires a prescribing physician, because the right schedule depends on how long you have been on the drug, your current dose, your age, liver function, and other medications. Starting a new drug at 50-75% of the calculated equivalent is common clinical practice, but even that rule has exceptions.
Why is lorazepam 1 mg equivalent to diazepam 10 mg?
Lorazepam (Ativan) is roughly 10 times more potent per milligram than diazepam. So 1 mg of lorazepam produces an effect comparable to 10 mg of diazepam. Both bind GABA-A receptors, but lorazepam has higher receptor affinity, resulting in a much lower effective dose by weight.
What is the difference between short, intermediate, and long-duration benzodiazepines?
Duration refers to how long the drug (and any active metabolites) remains active in the body, largely determined by half-life. Short-duration drugs (triazolam, midazolam) have half-lives of a few hours and wear off quickly. Intermediate-duration drugs (lorazepam, alprazolam) last 10-27 hours. Long-duration drugs (diazepam, clonazepam) have half-lives of 20-100 hours, which is why they are preferred for tapering: the slow elimination softens withdrawal.