Opioid to Oral Morphine Equivalent (OME) Calculator

Based on ANZCA Faculty of Pain Medicine PS01(PM) 2021 Guidelines

ANZCA Opioid Conversion Factors

Opioid Oral (mg) Parenteral (mg) Parenteral (mcg) Transdermal (mcg/hr) Sublingual (mg)
Morphine 1 3 0.003 - -
Oxycodone (Endone, OxyContin) 1.5 3 0.003 - -
Hydromorphone (Dilaudid) 5 15 0.015 - -
Codeine 0.13 0.25 0.00025 - -
Tramadol 0.2 0.2 0.0002 - -
Tapentadol (Palexia) 0.3 0.3 0.0003 - -
Fentanyl - 200 0.2 3 -
Buprenorphine (Norspan) - - - 2 40
Pethidine 0.4 0.4 0.0004 - -
Sufentanil - 2000 2 - -

Note: Conversion factors show how many mg of morphine equivalent each unit provides. For parenteral routes, IT (intrathecal) uses the same factors as IV/IM/SC. A dash (-) indicates the route is not typically used for that medication.
Important: Transdermal patch factors (mcg/hr) already give the daily OME - do not multiply by 24.

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Note: Values are assumed to be daily totals unless frequency is specified (e.g., "5mg BD" = 10mg daily)

Test Calculator

Enter an opioid regimen to test the calculation:

Unit tests run automatically on page load

Examples:
  • "fentanyl 90mcg IV, intrathecal morphine 100mcg, endone 5mg" → 25.8mg
  • "intrathecal fentanyl 15mcg, intrathecal morphine 100mcg, endone 5mg" → 10.8mg
  • "5mg endone" → 7.5mg
  • "morphine 10mg BD" → 20mg (frequency multiplier applied)
  • "oxycodone 5mg TDS" → 22.5mg (5mg × 3 times × 1.5 factor)