Clinical calculator
MME Calculator
Morphine Milligram Equivalent (MME) Calculator
The morphine milligram equivalent calculator converts the total daily dose of one or more opioids into a single morphine-equivalent figure, used to assess cumulative opioid exposure and overdose risk, where 50 MME per day and above warrants careful review.
What the MME score means
MME scores run from 0 to 200, where a lower score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Low daily dose0–19.9
Below 20 MME per day. Overdose risk attributable to dose is low, though it is never zero, particularly with concurrent benzodiazepines.
- Moderate daily dose20–49.9
Between 20 and 50 MME per day. Risk of overdose rises measurably across this range compared with lower doses.
- High daily dose50–89.9
At or above 50 MME per day. The 2022 CDC guideline advises careful reassessment of benefit versus harm at this level, and that naloxone be offered.
- Very high daily dose90–100000
At or above 90 MME per day. Associated with a substantially increased risk of overdose. The 2022 CDC guideline explicitly warns against applying this as a hard cut-off or forcing abrupt tapers.
Published criteria and reliability
The published cut-offs that define this instrument, and the measured agreement between observers using it. Each is reported with the population it was derived in.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| Criterion | ≥ 50 MME/day — reassess benefit versus harm carefully and offer naloxone | — | Adults on opioid therapy for chronic pain | — | Dowell D 2022 |
| Criterion | ≥ 90 MME/day — substantially increased overdose risk; avoid or justify carefully | — | Adults on opioid therapy for chronic pain | — | Dowell D 2016 |
| Criterion | Overdose risk approximately doubles at 20–50 MME/day compared with under 20 | — | Cohort studies of opioid-treated patients | — | Dunn KM 2010 |
| Criterion | Thresholds are not hard limits and must not trigger abrupt tapering or discontinuation | — | 2022 CDC clinical practice guideline | — | Dowell D 2022 |
Criterion is a published cut-off, definition or performance figure belonging to a classification or decision rule — it is not a change score and should not be read as one.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Each opioid’s total daily dose in milligrams is multiplied by its CDC conversion factor, and the products are summed to give the total morphine milligram equivalents per day. The factors used are: codeine 0.15, hydrocodone 1, hydromorphone 4, morphine 1, oxycodone 1.5, oxymorphone 3, and tramadol 0.1. Transdermal fentanyl is multiplied by 2.4 applied to the patch strength in micrograms per hour rather than to a milligram dose. Methadone uses a dose-dependent factor because its potency relative to morphine increases with dose: 4 at 20 mg per day or less, 8 from 21 to 40 mg, 10 from 41 to 60 mg, and 12 above 60 mg per day.
Missing data
Only the opioids a patient actually takes need to be entered; blank fields contribute zero. An entry of zero is treated the same as a blank.
Instrument profile
- Developer
- Centers for Disease Control and Prevention
- Institution
- CDC, United States
- First published
- 2016
- Custodian
- CDC, conversion table revised 2022
- Response format
- Total daily dose per opioid, in milligrams (or micrograms per hour for patches)
- Score range
- 0 to 200
- Direction
- Lower score = better
- Recall period
- Total dose in a 24-hour period
- Completion time
- About 2 minutes
- Age range
- Adults
- Regions
- General Health
- Conditions
- Chronic pain, Post-operative pain, Opioid therapy, Opioid overdose risk
- Procedures
- Post-operative analgesia, Opioid tapering, Pain management review
- Validity
- MME correlates with overdose risk across large cohort studies and is the standard measure of cumulative opioid exposure in prescribing surveillance and research.
- Reliability
- Conversion factors are population averages and do not account for individual pharmacogenomics, renal or hepatic function, or incomplete cross-tolerance. They were derived for risk surveillance, not for bedside opioid rotation, and using them for direct substitution has caused fatal overdoses.
When to use the MME
Well suited to
- Assessing total opioid exposure in a patient on one or more opioids, particularly before escalating a dose.
- Identifying patients who should be offered take-home naloxone.
- Prescribing audit, surveillance and research, where MME is the standard unit.
Limitations and poor fits
- To convert one opioid to another at an equivalent dose — incomplete cross-tolerance means the calculated equivalent dose is dangerous, and any rotation requires a substantial reduction and retitration.
- For buprenorphine, a partial agonist for which MME conversion is not meaningful.
- In palliative, end-of-life or cancer pain care, where the CDC thresholds explicitly do not apply.
- As a justification for abrupt tapering or discontinuation, which the 2022 guideline warns against directly.
MME compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| PSEQ | 10 | 0–60 | The Pain Self-Efficacy Questionnaire measures how confident a person is in carrying out activities despite their pain, scoring ten statements from 0 to 6 for a total of 0 to 60, where higher scores indicate stronger self-efficacy and 40 or more is the commonly cited threshold for a good functional prognosis. |
| CCI | 17 | 0–37 | The Charlson Comorbidity Index is a weighted checklist of 16 comorbid conditions that produces a comorbidity score of 0 to 33, to which up to 4 points are added for age, and which estimates 10-year survival at roughly 98% for a total of 0, 90% for 2, 53% for 4 and 21% for 5. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
The CDC conversion factors are published openly by the Centers for Disease Control and Prevention as United States government work, and are freely reproducible.
References
- Dowell D, Haegerich TM, Chou R. CDC guideline for prescribing opioids for chronic pain — United States, 2016. MMWR Recommendations and Reports. 2016.PMID 26987082
- Dowell D, Ragan KR, Jones CM, Baldwin GT, Chou R. CDC clinical practice guideline for prescribing opioids for pain — United States, 2022. MMWR Recommendations and Reports. 2022.PMID 36327391
- Dunn KM, Saunders KW, Rutter CM, et al.. Opioid prescriptions for chronic pain and overdose: a cohort study. Annals of Internal Medicine. 2010.PMID 20083827
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.