Calculate total daily morphine milligram equivalents (MME) from one or more opioids, see the CDC risk band, or work backward from a target MME.
Morphine Milligram Equivalent (MME) Formula
For a single opioid, the daily morphine milligram equivalent is the daily dose multiplied by that opioid's conversion factor:
Daily MME = Dose per administration * Doses per day * CF
When a person takes more than one opioid, you work out the MME for each drug and add them together for the total daily exposure:
Total MME/day = MME(drug 1) + MME(drug 2) + ...
Two opioids use a different rule. A fentanyl patch is dosed in micrograms per hour, and its factor already covers a full day, so you multiply the patch rate by 2.4:
Fentanyl patch MME/day = Patch rate (mcg/hr) * 2.4
Methadone uses a factor that rises with the total daily methadone dose:
Methadone MME/day = Daily methadone (mg) * tier factor tier factor = 4, 8, 10, or 12
To work backward from a goal, the target mode rearranges the single drug formula to find the dose that matches a chosen MME:
Required daily dose = Target MME / CF
Variables:
- Dose per administration is the strength of one dose, in milligrams for oral opioids or micrograms per hour for a fentanyl patch
- Doses per day is the number of administrations in 24 hours, or the number of patches worn at once
- CF is the opioid's morphine conversion factor from the CDC table
- Total MME/day is the sum of the daily MME for every opioid in the regimen
- Tier factor is the methadone factor set by the total daily methadone dose: 4 at 1 to 20 mg, 8 at 21 to 40 mg, 10 at 41 to 60 mg, and 12 above 60 mg
The calculator has two modes. Total mode adds every opioid you enter and returns one daily MME, the CDC risk band, and a naloxone prompt when the total reaches 50 MME or a sedative is also in use. Target mode does the reverse: you give it an MME goal and an opioid, and it returns the daily dose that matches, which helps when you are planning a taper or a switch between opioids.
Opioid Conversion Factors and Typical Daily MME
The first table lists the morphine conversion factor for each opioid the calculator supports. Oral opioids are entered in milligrams, and the fentanyl patch is entered in micrograms per hour.
| Opioid | Conversion factor | Dose unit |
|---|---|---|
| Morphine | 1 | mg |
| Codeine | 0.15 | mg |
| Hydrocodone | 1 | mg |
| Oxycodone | 1.5 | mg |
| Hydromorphone | 4 | mg |
| Oxymorphone | 3 | mg |
| Tramadol | 0.1 | mg |
| Tapentadol | 0.4 | mg |
| Meperidine | 0.1 | mg |
| Levorphanol | 11 | mg |
| Methadone | 4 to 12 (by daily dose) | mg |
| Fentanyl patch | 2.4 | mcg/hr |
The second table converts common real prescriptions into a total daily MME and shows the CDC risk band each one falls in. Use it as a quick sanity check against your own result. Look at the fentanyl patch row in particular: a 25 mcg/hr patch is 60 MME per day, not the far larger number you get if you wrongly multiply the 2.4 factor by 24 a second time.
| Prescription | Daily MME | CDC risk band |
|---|---|---|
| Hydrocodone 5 mg, 3 times a day | 15 | Lower |
| Tramadol 50 mg, 4 times a day | 20 | Lower |
| Oxycodone 5 mg, 4 times a day | 30 | Lower |
| Morphine ER 30 mg, 2 times a day | 60 | Increased |
| Oxycodone 10 mg, 4 times a day | 60 | Increased |
| Hydromorphone 4 mg, 4 times a day | 64 | Increased |
| Fentanyl patch 25 mcg/hr | 60 | Increased |
| Oxycodone 20 mg, 3 times a day | 90 | High |
| Methadone 10 mg, 3 times a day | 240 | High |
CDC guidance treats 50 MME per day as the point to reassess the benefits and risks of continuing and to consider offering naloxone, and 90 MME per day as the point to avoid or carefully justify. These are screening lines, not hard limits, and some cancer or palliative care regimens sit above them on purpose with extra safeguards in place.
Example Problems
Example 1: a regimen with two opioids. You take oxycodone 15 mg three times a day and morphine ER 30 mg twice a day. The oxycodone daily dose is 15 * 3 = 45 mg, and 45 * 1.5 = 67.5 MME. The morphine daily dose is 30 * 2 = 60 mg, and 60 * 1 = 60 MME. Add them together: 67.5 + 60 = 127.5 MME per day, which sits in the high risk band above 90 MME.
Example 2: a fentanyl patch. You wear one 25 mcg/hr transdermal fentanyl patch. Multiply the rate by the patch factor: 25 * 2.4 = 60 MME per day. That is the entire daily total, because the 2.4 factor already accounts for 24 hours of delivery. Multiplying by 24 again is a common error that would overstate the dose by 24 times.
Frequently Asked Questions
What counts as a high MME per day?
The CDC uses two thresholds. At 50 MME per day you reassess whether the benefits still outweigh the risks, and offering naloxone is recommended. At 90 MME per day you either avoid the increase or carefully justify it, because the risk of overdose climbs sharply above that level. Anything under 50 MME is the lower risk band, though no opioid dose is completely risk free.
How do you calculate MME for a fentanyl patch?
Multiply the patch rate in micrograms per hour by 2.4. A 25 mcg/hr patch is 25 * 2.4 = 60 MME per day, a 50 mcg/hr patch is 120 MME per day, and a 100 mcg/hr patch is 240 MME per day. Do not multiply by 24 on top of the 2.4, because the factor already covers a full 24 hour day of patch delivery.
Why is buprenorphine not in the calculator?
Buprenorphine is a partial agonist with a ceiling on its opioid effect, so a straight morphine conversion tends to overstate its risk, and the published factors for it vary widely. It is often left out of MME totals for that reason, especially the film and tablet forms used to treat opioid use disorder. If you need a buprenorphine figure, ask a pharmacist to apply your local protocol.