Opioid MME calculator (morphine milligram equivalents)

Morphine Milligram Equivalents (MME) put every opioid on one scale — the daily dose expressed as if it were oral morphine. Clinicians, pharmacists, and health systems use it to gauge overdose risk, compare regimens, and flag when a total dose reaches thresholds (around 50 MME/day) where the CDC advises reassessing benefits, risks, and naloxone co-prescribing.

By the pharmaranks editorial teamReviewed against the CDC, the National Kidney Foundation & the primary literature sourcesHow we research

Enter the total DAILY dose of each opioid the person takes. Leave the rest blank.

Codeine (mg/day)

Hydrocodone (mg/day)

Hydromorphone (mg/day)

Morphine (mg/day)

Oxycodone (mg/day)

Oxymorphone (mg/day)

Tapentadol (mg/day)

Tramadol (mg/day)

Fentanyl transdermal patch (mcg/hr)

How it works

For each opioid you take, multiply the total milligrams per day by that drug's CDC conversion factor, then add the products together. In plain terms: MME/day = sum of (mg per day × factor). Factors: morphine and hydrocodone 1, oxycodone 1.5, oxymorphone 3, hydromorphone 4, tapentadol 0.4, codeine 0.15, tramadol 0.1. Transdermal fentanyl is separate: MME/day = patch rate in mcg/hr × 2.4. Methadone and buprenorphine are deliberately excluded — they need specialist conversion.

Worked example

A patient takes oxycodone 10 mg four times daily and tramadol 50 mg three times daily. Oxycodone: 40 mg/day × 1.5 = 60 MME. Tramadol: 150 mg/day × 0.1 = 15 MME. Total = 75 MME/day. That sits above the 50 MME/day mark where CDC suggests reassessing the regimen and offering naloxone — but it is a risk signal for a conversation with the prescriber, not a command to cut the dose.

Important

Estimate only. This calculator does not replace clinical judgment, a pharmacist's review, or the manufacturer's prescribing information. Its conversion factors are intended for analytic, population-level risk assessment — NOT for switching a patient from one opioid to another; the CDC states the new opioid must be dosed lower to account for incomplete cross-tolerance and individual pharmacokinetics. Transdermal fentanyl must be entered as the patch DELIVERY RATE in mcg/hr (e.g., 25 mcg/hr), never as milligrams or number of patches. Methadone (dose-dependent, tiered conversion factor) and buprenorphine (partial agonist with a ceiling effect) are deliberately excluded here and require specialist conversion — if you take either, your true total is higher than shown and this estimate is incomplete. Critically, per the CDC 2022 Clinical Practice Guideline, MME must NOT be used to justify abrupt tapering or rigid dose thresholds; rapid dose reduction or discontinuation can cause withdrawal, uncontrolled pain, and serious harm, including in some cases overdose or crisis. Absorption of fentanyl is affected by heat and other factors. Never start, stop, or change an opioid dose without your prescriber.

Sources

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