How to Use Opioid Conversion Calculator
The Opioid Conversion Calculator is meant for a single equianalgesic comparison: one current opioid, one target opioid, and one current dose. Start by choosing the current opioid from the list, then choose the opioid you want to compare against. Enter the current dose as the amount represented by the selected drug and press the calculation button or let the page update the result.
The output shows the estimated target dose, the factor assigned to the current opioid, and the factor assigned to the target opioid. This is useful because a surprising result can usually be explained by one of those two factors. For example, moving from a drug with a high factor to a drug with a lower factor increases the displayed target dose, while the reverse lowers it.
Use the result as a calculation check, not as a direct conversion order. Real opioid rotation also depends on route, tolerance, age, organ function, pain severity, concurrent sedatives, and local prescribing protocols.
Formula & Theory — Opioid Conversion Calculator
The Opioid Conversion Calculator uses the following formula or scoring rule:
target dose = current dose × (current opioid factor ÷ target opioid factor)The Opioid Conversion Calculator treats every listed opioid as a relative potency factor. The current dose is first converted into the reference scale by multiplying by the current factor. That reference amount is then divided by the target factor to estimate the target drug dose.
Because the calculation is ratio-based, the absolute size of the factor table matters less than the relationship between two selected drugs. A target factor twice as large as the current factor produces roughly half the current dose; a target factor half as large produces roughly double the dose.
Equianalgesic tables are simplifications. They do not capture incomplete cross-tolerance, active metabolites, opioid-naive status, long-acting formulations, or patient-specific sensitivity.
Use Cases for Opioid Conversion Calculator
The Opioid Conversion Calculator is useful in specific situations such as:
- checking the arithmetic behind an opioid rotation discussion before applying clinical dose-reduction rules
- teaching why different opioids cannot be compared by milligrams alone
- reviewing a pain-management worksheet where the current drug and target drug are both listed
- documenting which conversion factors were used in a training example