Opioid Conversion Calculator – MME
Quickly add up a patient's total daily opioid dose in morphine milligram equivalents (MME/day) using CDC 2022 conversion factors. Enter up to 6 medications with strength, units per dose and doses per day to get the total plus per-medication breakdown and CDC threshold guidance.
Add Up a Patient's Total Daily Opioid Dose in Morphine Equivalents
MME Formula
Where:
- \(S\) — strength per unit: milligrams per tablet, capsule or mL
- \(U\) — units per dose, e.g. tablets or capsules taken at one time
- \(D\) — doses taken per day
- \(F\) — CDC 2022 conversion factor to morphine equivalents (e.g. oxycodone 1.5, tramadol 0.2)
- \(n\) — number of opioid medications the patient takes (1 to 6)
The formula converts the total daily amount of each opioid into its morphine milligram equivalent using the CDC 2022 conversion factors, then adds them together to express the combined daily opioid burden as a single number.
MME – Calculation Example
Example: a patient takes oxycodone 5 mg tablets, one tablet four times a day, and tramadol 50 mg capsules, one capsule three times a day. These are the calculator's default values.
\[ \text{Oxycodone: } 5 \times 1 \times 4 \times 1.5 = 30 \text{ MME/day} \]
\[ \text{Tramadol: } 50 \times 1 \times 3 \times 0.2 = 30 \text{ MME/day} \]
\[ \text{Total: } 30 + 30 = 60 \text{ MME/day} \]
Result: 60 MME/day — 30 from oxycodone and 30 from tramadol. Because the total is at or above 50 MME/day, the CDC recommends reassessing benefits and risks, considering a dose reduction, and taking additional precautions.
How to use the MME calculator
- Set Number of opioid medications to match the patient's regimen (1 to 6). The input rows for each extra medication appear automatically.
- For each medication, choose the opioid from the Opioid drop-down — the CDC 2022 conversion factor is shown in parentheses next to each option.
- Enter the Strength per unit: milligrams per tablet, capsule or mL. For a fentanyl transdermal patch, enter the delivery rate in mcg/hr instead.
- Enter Units per dose (e.g. 2 tablets) and Doses per day. These two fields are hidden for a fentanyl patch, because a patch delivers continuously and only the mcg/hr value matters.
- Press the calculate button. The results show the Total daily MME, the MME/day contributed by each medication, a line-by-line breakdown of the arithmetic, and CDC threshold guidance for the resulting dose.
- Hover over the question-mark icons next to the input fields for quick reminders of what each field expects.
What are morphine milligram equivalents?
Morphine milligram equivalents (MME) is a standard way of expressing the total amount of opioids a patient takes per day, converted into an equivalent dose of oral morphine. A patient on 60 MME/day is receiving an opioid burden comparable to 60 mg of oral morphine per day — regardless of whether the actual medications are tablets, capsules, solutions or patches, and regardless of how many different opioids are involved.
The main reason clinicians calculate MME is overdose risk. The CDC's 2022 Clinical Practice Guideline identified two decision points: at 50 MME/day the benefits should be carefully weighed against the risks, with consideration of tapering or reducing the dose, closer monitoring, offering naloxone, and avoiding concurrent benzodiazepines and alcohol. At 90 MME/day the CDC recommends avoiding this dose range altogether, because overdose risk rises substantially; continuing at such doses requires documented justification, frequent reassessment and, where possible, specialist involvement.
MME is also useful in everyday practice for spotting hidden opioid burden. A patient may appear to be on a "modest" dose of tramadol plus oxycodone, yet the combined MME can exceed a safety threshold that neither prescription alone would suggest. Pharmacists also use MME when checking prescription drug monitoring program (PDMP) data for cumulative opioid exposure across prescribers.
Interpreting the result requires context: MME is a measure of opioid burden, not of pain relief or of how much opioid is actually absorbed. Some patients metabolize codeine and tramadol poorly and get little effect, while others are ultra-rapid metabolizers. Two patients with the same MME can have very different clinical situations, so the number supports — but never replaces — clinical judgement. If a patient is on multiple opioids, similar dose-checking logic may apply to other medications; our liquid dose calculator and tablet dose calculator can help verify individual prescription dosages.
Conversion factors used (CDC 2022)
| Opioid | Conversion factor | MME per unit of drug |
|---|---|---|
| Codeine | 0.15 | 1 mg = 0.15 MME |
| Fentanyl transdermal patch | 2.4 | 1 mcg/hr = 2.4 MME/day |
| Hydrocodone | 1 | 1 mg = 1 MME |
| Hydromorphone | 5 | 1 mg = 5 MME |
| Methadone | 4.7 | 1 mg = 4.7 MME |
| Morphine | 1 | 1 mg = 1 MME (reference) |
| Oxycodone | 1.5 | 1 mg = 1.5 MME |
| Oxymorphone | 3 | 1 mg = 3 MME |
| Tapentadol | 0.4 | 1 mg = 0.4 MME |
| Tramadol | 0.2 | 1 mg = 0.2 MME |
Limitations and practical tips
- Never use MME factors to convert or switch opioids. The CDC is explicit that these conversion factors estimate total opioid burden only. Directly switching a patient from one opioid to another using these factors can cause serious under- or overdosing.
- Methadone is not linear. Its analgesic effect does not scale with dose the way a single factor suggests, and it accumulates over time due to its long half-life — methadone dosing changes should always be made by an experienced clinician.
- Tramadol and tapentadol factors are approximations. Their MME equivalence depends on metabolism, which varies between patients.
- Buprenorphine is excluded because the CDC 2022 guideline gives no conversion factor for it.
- Verify the actual prescription. Check product strength, tablet or capsule count, dosing frequency and directions before relying on the result — implied "as needed" usage may differ from what patients actually take.
- The 50 and 90 MME/day values are precautionary checkpoints, not absolute limits. Some clinical situations (cancer pain, palliative care, opioid use disorder treatment) call for different considerations than the general guideline.
- When reviewing a complex regimen, a Drug Abuse Screening Test (DAST) may complement the MME figure when evaluating risk, and the half-life calculator can help understand accumulation with long-acting opioids like methadone.
This calculator is a calculation aid for clinicians and pharmacy professionals, not medical advice and not a substitute for the full CDC 2022 Clinical Practice Guideline or individual clinical assessment.
Frequently Asked Questions
How do I calculate MME by hand?
Multiply the drug amount per day by its conversion factor. For example, hydrocodone 10 mg × 6 tablets/day = 60 mg/day, and since the factor is 1, that equals \(60 \times 1 = 60\) MME/day. For oxycodone 5 mg × 4 tablets/day = 20 mg/day, multiply by 1.5 to get \(20 \times 1.5 = 30\) MME/day. Add each opioid's result to get the daily total.
What is a normal or safe MME per day?
There is no completely "safe" dose — the CDC 2022 guideline says to use the lowest effective dose for the shortest appropriate time. Two checkpoints matter: at 50 MME/day, carefully reassess benefits and risks and consider naloxone; at 90 MME/day overdose risk rises substantially and the CDC recommends avoiding this range. Many patients are managed well below 50 MME/day. This is guidance for clinicians, not a rule for self-adjusting medication — never change your own opioid dose without medical advice.
How do I count a fentanyl patch in the MME calculation?
Enter only the patch's delivery rate in mcg/hr — the units-per-dose and doses-per-day fields do not apply. A 25 mcg/hr patch equals \(25 \times 2.4 = 60\) MME/day, whether it is changed every 48 or 72 hours, because delivery is continuous. The 2.4 factor applies to transdermal patches only; do not use it for IV, buccal or sublingual fentanyl.
How do I calculate MME for an as-needed (PRN) prescription?
Estimate the patient's actual daily usage rather than the maximum allowed. If the label says "1 tablet every 6 hours as needed" but the patient typically takes 3 tablets a day, use 3 doses per day. For prescriptions filled historically, an alternative is total mg dispensed divided by days supply: 90 tablets of oxycodone 5 mg over 30 days is \(90 \times 5 \div 30 = 15\) mg/day, or 22.5 MME/day.
Why did the methadone conversion factor change from the CDC 2016 guideline?
The 2016 guideline used a tiered schedule (factors rising from 3 up to 12 as the daily methadone dose increased) to reflect that methadone is stronger per milligram at higher doses. The 2022 guideline dropped the tiers in favor of a simplified factor of 4.7, while stressing that methadone is nonlinear, accumulates and must be dosed by experienced clinicians — the factor only estimates total burden.
How do I enter a liquid opioid solution?
Enter the concentration as the strength in mg per mL, then use the volume taken at one time as units per dose. For morphine solution 2 mg/mL, a 5 mL dose given 4 times a day: strength 2 mg/mL, units per dose 5 mL, doses per day 4, giving \(2 \times 5 \times 4 \times 1 = 40\) MME/day. Check the label carefully — oral solutions are supplied in many different concentrations.
Is MME the same as OME?
They mean the same thing: morphine milligram equivalents (MME) and oral morphine equivalents (OME) both express a daily opioid dose as equivalent milligrams of oral morphine, and the numbers are used interchangeably in practice. "OME" was more common in older literature and some countries, while "MME" is the CDC's preferred term. The result of this calculator can be read either way.