Estimate total daily morphine milligram equivalents (MME) for up to four prescribed opioids using CDC 2022 conversion factors, for clinical review.
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) + ...
A fentanyl patch is entered in micrograms per hour. Its factor already covers a full day, so multiply the combined rate of simultaneous patches by 2.4:
Fentanyl patch MME/day = Patch rate (mcg/hr) * 2.4
The CDC 2022 table uses 4.7 for oral methadone prescribed for pain. This replaces the older dose-tier approach; it does not establish a safe methadone dose:
Methadone MME/day = Daily methadone (mg) * 4.7
MME is an exposure estimate. Do not rearrange this calculation to select an opioid dose or to switch between opioids:
MME arithmetic is not an opioid prescribing conversion.
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
- Methadone uses the CDC 2022 factor 4.7; its variable half-life and delayed respiratory depression require particular caution
Choose one to four opioids and enter each dose and frequency. The calculator sums daily MME and displays relevant clinical-review cautions. The former reverse-dose mode was removed because CDC cautions against using MME to determine opioid-switch doses. Tapering requires an individualized clinical plan, without abrupt discontinuation.
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 | 5 | mg |
| Oxymorphone | 3 | mg |
| Tramadol | 0.2 | mg |
| Tapentadol | 0.4 | mg |
| Methadone | 4.7 | mg |
| Fentanyl patch | 2.4 | mcg/hr |
The second table gives arithmetic examples, not recommended prescriptions. The clinical-review column flags totals at or above 50 MME/day without classifying lower amounts as safe. A 25 mcg/hour fentanyl patch is 60 MME/day; do not multiply its 2.4 factor by 24 again.
| Prescription | Daily MME | Clinical review |
|---|---|---|
| Hydrocodone 5 mg, 3 times a day | 15 | Below 50; safety not established |
| Tramadol 50 mg, 4 times a day | 40 | Below 50; safety not established |
| Oxycodone 5 mg, 4 times a day | 30 | Below 50; safety not established |
| Morphine ER 30 mg, 2 times a day | 60 | At least 50; reassess |
| Oxycodone 10 mg, 4 times a day | 60 | At least 50; reassess |
| Hydromorphone 4 mg, 4 times a day | 80 | At least 50; reassess |
| Fentanyl patch 25 mcg/hr | 60 | At least 50; reassess |
| Oxycodone 20 mg, 3 times a day | 90 | At least 50; reassess |
| Methadone 10 mg, 3 times a day | 141 | At least 50; reassess |
CDC 2022 recommends reassessing benefits and risks before increasing to 50 MME/day or more, and additional precautions at that level, including offering naloxone and overdose-prevention education. It does not define safe/unsafe risk bands or a total MME limit. Its recommendations exclude sickle cell disease, cancer pain treatment, palliative and end-of-life care.
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. This exceeds the 50 MME/day clinical-reassessment guidepost, without determining an individual safe dose.
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?
Overdose risk generally increases with dose, but no MME value determines safety for an individual. CDC 2022 uses 50 MME/day as a guidepost for reassessment and added precautions, not a rigid limit. Discuss medication decisions with the prescriber; do not change or abruptly stop opioids using this estimate.
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.
