Benzodiazepine Conversion Calculator and Equivalence Chart
Convert a daily dose of one benzodiazepine into the approximate equivalent dose of another, using the equivalence table in the Ashton Manual.
Approximate equivalent doses from Table 1 of the Ashton Manual
This calculator is an educational planning tool. It is not medical advice and it is not a substitute for supervision by a physician who knows your history. Whether to taper, and how fast, are decisions for you and your prescriber. Never stop a benzodiazepine abruptly.
Benzodiazepine equivalence chart from the Ashton Manual
The calculator uses Table 1 of the Ashton Manual, written by Professor C. Heather Ashton. The table gives the oral dose of each drug that is approximately equivalent to 10 mg of diazepam (Valium), along with each drug’s half-life. A smaller number in the dose column means a more potent drug per milligram.
| Drug | Brand names in the Manual | Dose equivalent to 10 mg diazepam | Half-life (hours) |
|---|---|---|---|
| Alprazolam | Xanax, Xanor, Tafil | 0.5 mg | 6 to 12 |
| Bromazepam | Lexotan, Lexomil | 5 to 6 mg | 10 to 20 |
| Chlordiazepoxide | Librium | 25 mg | 5 to 30 (36 to 200) |
| Clobazam | Frisium | 20 mg | 12 to 60 |
| Clonazepam | Klonopin, Rivotril | 0.5 mg | 18 to 50 |
| Clorazepate | Tranxene | 15 mg | (36 to 200) |
| Diazepam | Valium | 10 mg | 20 to 100 (36 to 200) |
| Estazolam | ProSom, Nuctalon | 1 to 2 mg | 10 to 24 |
| Flunitrazepam | Rohypnol | 1 mg | 18 to 26 (36 to 200) |
| Flurazepam | Dalmane | 15 to 30 mg | (40 to 250) |
| Halazepam | Paxipam | 20 mg | (30 to 100) |
| Ketazolam | Anxon | 15 to 30 mg | 30 to 100 (36 to 200) |
| Loprazolam | Dormonoct | 1 to 2 mg | 6 to 12 |
| Lorazepam | Ativan, Temesta, Tavor | 1 mg | 10 to 20 |
| Lormetazepam | Noctamid | 1 to 2 mg | 10 to 12 |
| Medazepam | Nobrium | 10 mg | 36 to 200 |
| Nitrazepam | Mogadon | 10 mg | 15 to 38 |
| Nordazepam | Nordaz, Calmday | 10 mg | 36 to 200 |
| Oxazepam | Serax, Serenid, Serepax, Seresta | 20 mg | 4 to 15 |
| Prazepam | Centrax, Lysanxia | 10 to 20 mg | (36 to 200) |
| Quazepam | Doral | 20 mg | 25 to 100 |
| Temazepam | Restoril, Normison, Euhypnos | 20 mg | 8 to 22 |
| Triazolam | Halcion | 0.5 mg | 2 |
| Non-benzodiazepines with similar effects (z-drugs) | |||
| Zaleplon | Sonata | 20 mg | 2 |
| Zolpidem | Ambien, Stilnoct, Stilnox | 20 mg | 2 |
| Zopiclone | Zimovane, Imovane | 15 mg | 5 to 6 |
| Eszopiclone | Lunesta | 3 mg | 6 (9 in older adults) |
A half-life in parentheses belongs to a long-lasting active metabolite, a substance the body makes from the drug that keeps working after the drug itself has gone. The Manual was written for readers in many countries, so the table includes drugs that are not sold in the United States.
Common benzodiazepine conversions
These are the conversions people look up most often. Each line is arithmetic on the Manual’s table and nothing more.
| Conversion | Generic names | What the Manual’s table gives |
|---|---|---|
| Xanax to Valium | alprazolam to diazepam | 0.5 mg of alprazolam is about 10 mg of diazepam, so 1 mg is about 20 mg and 2 mg is about 40 mg |
| Klonopin to Valium | clonazepam to diazepam | 0.5 mg of clonazepam is about 10 mg of diazepam, so 1 mg is about 20 mg |
| Ativan to Valium | lorazepam to diazepam | 1 mg of lorazepam is about 10 mg of diazepam, so 2 mg is about 20 mg |
| Ativan to Klonopin | lorazepam to clonazepam | 1 mg of lorazepam is about 0.5 mg of clonazepam |
| Xanax to Klonopin | alprazolam to clonazepam | 1 mg of alprazolam is about 1 mg of clonazepam |
| Xanax to Ativan | alprazolam to lorazepam | 0.5 mg of alprazolam is about 1 mg of lorazepam |
| Restoril to Valium | temazepam to diazepam | 20 mg of temazepam is about 10 mg of diazepam |
| Librium to Valium | chlordiazepoxide to diazepam | 25 mg of chlordiazepoxide is about 10 mg of diazepam |
| Ambien to Valium | zolpidem to diazepam | 20 mg of zolpidem is about 10 mg of diazepam |
The figures describe strength. They are not a plan for changing medication, and no dose should be changed without the prescriber.
Equal strength is not equal duration
The Manual says its equivalents are approximate. The footnote to the table explains that they are based on clinical experience during the switch to diazepam at the start of withdrawal, that they do not agree with the figures some other authors use, and that they may vary between individuals. Two charts can disagree without either one being careless.
Strength is also only half of the picture. In the table, 1 mg of lorazepam and 10 mg of diazepam are equal in strength, but lorazepam has a half-life of 10 to 20 hours and diazepam has a half-life of 20 to 100 hours. A short-acting drug can wear off between doses. Diazepam leaves the body slowly, which is one reason the Manual uses it for the crossover taper.
People who look up a conversion have usually taken a benzodiazepine as prescribed for a long time. Physical dependence is not addiction. It is the body’s expected adaptation to a medicine taken regularly, and it is the reason any change of drug or dose is made gradually.
A crossover is not made in one day. The Manual describes substituting one dose at a time, usually starting with the evening or night-time dose, then replacing the other doses one by one. The result is adjusted to the person, with the prescriber.
For more detail, read the Ashton Manual equivalence table explained and how Xanax to Valium conversion works in practice. The Ashton Manual Guide calculator lays out a crossover and reduction in the shape of the Manual’s schedules.
Questions about benzodiazepine conversion
How many mg of Valium equal 1 mg of Xanax?
In the Ashton Manual’s table, 0.5 mg of alprazolam (Xanax) is approximately equivalent to 10 mg of diazepam (Valium). That makes 1 mg of Xanax about 20 mg of Valium, and 2 mg about 40 mg. The Manual calls these figures approximate, and a switch between the two drugs is made in stages with a prescriber.
How much Klonopin is equivalent to Xanax?
Milligram for milligram they are about equal in the Manual’s table. Both 0.5 mg of clonazepam (Klonopin) and 0.5 mg of alprazolam (Xanax) match about 10 mg of diazepam, so 2 mg of Xanax is about 2 mg of Klonopin. The difference is duration: the half-life of clonazepam is 18 to 50 hours and the half-life of alprazolam is 6 to 12 hours.
How do you convert Ativan to Valium?
The table gives 1 mg of lorazepam (Ativan) as approximately equivalent to 10 mg of diazepam (Valium), so the daily lorazepam dose multiplied by 10 gives the approximate diazepam equivalent. The Manual describes making the change one dose at a time, with the prescriber adjusting the result to the person.
Is Klonopin stronger than Ativan?
Per milligram, yes. In the Manual’s table 0.5 mg of clonazepam (Klonopin) and 1 mg of lorazepam (Ativan) each match about 10 mg of diazepam, so 1 mg of Ativan is about 0.5 mg of Klonopin. Clonazepam also lasts longer, with a half-life of 18 to 50 hours against 10 to 20 hours for lorazepam.
What is the strongest benzodiazepine?
Per milligram, the most potent drugs in the Manual’s table are alprazolam (Xanax), clonazepam (Klonopin) and triazolam (Halcion). Half a milligram of each is approximately equivalent to 10 mg of diazepam. Potency per milligram is a different thing from how long a drug lasts, which the half-life column shows.
Are benzodiazepine conversions exact?
No. The Manual’s own footnote says its equivalents do not agree with those used by some authors and may vary between individuals. A converted dose is a starting point for a conversation with a prescriber, who adjusts it to the person.
Where do the numbers in this calculator come from?
They come from Table 1 of the Ashton Manual, “Benzodiazepines: How They Work and How to Withdraw”, by Professor C. Heather Ashton. The calculator does arithmetic on that table and nothing else. This site is an independent educational reference and is not affiliated with Professor Ashton’s estate or Newcastle University.
Can this calculator plan a switch to diazepam?
No. It shows equivalent strength only. A crossover is made in stages over weeks, and the reduction that follows is planned with a prescriber. The Ashton Manual Guide calculator on this site shows how a crossover and taper of that shape is laid out.
Taper calculators on this site
Once the equivalent dose is known, these educational tools show how a gradual reduction is laid out.