OPRA Calculations Practice
Calculations are consistently the hardest part of OPRA. Drill every numeric type in our free Calculations Lab — values randomise on each attempt, so you learn the method, not the answer. No sign-up required.
Every OPRA calculation type
- Cockcroft-Gault creatinine clearance & renal dose adjustment
- Body-surface-area (BSA) chemotherapy dosing
- Opioid equianalgesic conversions
- Vancomycin AUC dosing & therapeutic drug monitoring
- mmol / mEq electrolyte calculations
- Alligation, dilutions and concentration problems
Practise the method, not the answer
Each scenario re-randomises the patient values, so you can't memorise your way through. Work it, check the full step-by-step solution, and repeat until the method is automatic.
Open the Calculations Lab
It's free and needs no account — start practising calculations right now.
Open Calc Lab — freeFrequently asked questions
Is the OPRA Calculations Lab free?
Yes — it's completely free and needs no sign-up.
Which calculation types are covered?
Cockcroft-Gault, BSA dosing, opioid conversions, vancomycin AUC/TDM, electrolyte (mmol/mEq), and alligation/dilution problems.
Do the numbers change each time?
Yes — values randomise on every attempt so you practise the method rather than memorising a single answer.