# MME Calculator (Morphine Milligram Equivalents)

Calculate Morphine Milligram Equivalents (MME) for opioid prescriptions using CDC conversion factors. Assess daily MME against CDC risk thresholds.

## What this calculates

Morphine Milligram Equivalents (MME) provide a standardized way to compare the potency of different opioid medications. Select your opioid, dose, and frequency to calculate your daily MME and see how it compares to CDC prescribing thresholds.

## Inputs

- **Opioid Medication** — options: Morphine, Oxycodone, Hydrocodone, Hydromorphone, Codeine, Tramadol, Fentanyl Patch (mcg/hr), Methadone (1-20 mg/day), Methadone (21-40 mg/day), Methadone (41-60 mg/day), Oxymorphone, Tapentadol
- **Dose per Administration** (mg) — min 0.1, max 2000 — Single dose in mg (or mcg/hr for fentanyl patch)
- **Doses per Day** — options: Once daily, Twice daily, Three times daily, Four times daily, Every 4 hours

## Outputs

- **Total Daily Dose** — Total daily dose of the selected opioid
- **Daily MME** — Morphine milligram equivalents per day
- **CDC Risk Threshold** — formatted as text — Risk category based on CDC prescribing guidelines
- **Conversion Factor Used** — formatted as text — The MME conversion factor for this opioid

## Details

MME converts any opioid dose into an equivalent amount of oral morphine using published conversion factors. For example, 10 mg of oxycodone is equivalent to 15 MME (conversion factor: 1.5), while 10 mg of hydromorphone equals 40 MME (conversion factor: 4).

The CDC's 2022 Clinical Practice Guideline for Prescribing Opioids identifies key MME thresholds:

- **Below 50 MME/day**: Standard prescribing range for most patients
- **50-89 MME/day**: Increased risk; reassess benefits vs. harms
- **90+ MME/day**: Substantially higher overdose risk; avoid or carefully justify

Research shows that patients receiving 90+ MME/day have a 2-9x higher risk of opioid overdose compared to those receiving less than 20 MME/day.

Conversion factors used here follow the CDC's published table. Methadone is unique because its conversion factor increases at higher doses due to its long and variable half-life. Fentanyl patches use mcg/hr as the unit since they deliver medication continuously through the skin.

**IMPORTANT: This calculator is for educational reference only.** Opioid dose conversions should never be used for direct clinical dose changes without professional oversight. Incomplete cross-tolerance means that switching between opioids typically requires reducing the calculated equianalgesic dose by 25-50%. Always consult a healthcare provider or clinical pharmacist for opioid prescribing decisions.

## Frequently Asked Questions

**Q: What does MME stand for?**

A: MME stands for Morphine Milligram Equivalents. It is a standardized measure that converts any opioid dose into the equivalent amount of oral morphine. This allows healthcare providers to compare the total opioid burden across different medications and assess risk. For example, 10 mg of oxycodone = 15 MME, meaning it has the analgesic potency of 15 mg of oral morphine.

**Q: Why is 90 MME per day considered high risk?**

A: The CDC identified 90 MME/day as a critical threshold based on epidemiological data showing that overdose risk increases substantially above this level. Studies have demonstrated a dose-response relationship between daily MME and overdose: patients at 100+ MME/day have a roughly 9-fold higher overdose risk compared to those at 1-20 MME/day. The 90 MME threshold is a clinical guideline, not an absolute cutoff, and individual risk varies.

**Q: Why are methadone conversion factors variable?**

A: Methadone has unique pharmacokinetics with a very long and variable half-life (8-59 hours). At higher doses, methadone's relative potency compared to morphine increases disproportionately. At 1-20 mg/day the conversion factor is 4, but at 41-60 mg/day it rises to 10. This non-linear relationship makes methadone dose conversions particularly complex and potentially dangerous without expert guidance.

**Q: Can I use MME to switch between opioids?**

A: While MME provides equianalgesic equivalence, you should NEVER use it for direct 1:1 conversion when switching opioids. Due to incomplete cross-tolerance between different opioids, the standard practice is to reduce the calculated equianalgesic dose by 25-50% when rotating to a new opioid. This critical safety step must be guided by a healthcare provider experienced in opioid management.

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Source: https://vastcalc.com/calculators/health/mme
Category: Health & Fitness
Last updated: 2026-04-08