Opioid Equianalgesic Conversion (rotation calculator)
Opioid equianalgesic / rotation converter: the source daily dose is converted to oral morphine equivalents and back to the target opioid, then reduced 0–50% for incomplete cross-tolerance.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Source opioid and route
- Morphine — oral (mg/day)
- Total source daily dose
- 60 mg or mcg/day
- Target opioid and route
- Oxycodone — oral (mg/day)
- Cross-tolerance reduction
- 50% (most conservative)
Result: Oral oxycodone 40 mg/day equianalgesic from 60 mg/day oral morphine; start 20 mg/day after a 50% reduction.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Fentanyl patch
- Target only, sized from the label Table 2 (60-134 mg/day oral morphine: 25 mcg/h; 135-224: 50; 225-314: 75; 315-404: 100). The label says its tables cannot be used to convert from the patch.
- Safety
- methadone and buprenorphine are excluded (non-linear/ceiling pharmacology). A planning aid only — confirm against protocol and an independent second check.
What you enter
- Source opioid and route
- Total source daily dose
- Target opioid and route
- Cross-tolerance reduction (r0/r25/r33/r50)
How this is calculated
- Method
- source daily dose → oral morphine equivalents (OME) → target opioid, then a 0–50% cross-tolerance reduction. OME: oxycodone 1.5, hydromorphone PO 4, IV morphine 3.
Citation
McPherson ML. Demystifying Opioid Conversion Calculations: A Guide for Effective Dosing. 2nd ed. Bethesda, MD: ASHP; 2018 (standard equianalgesic table). Confirm against institutional protocol and an independent second check. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.