PharmaceuticalCalculations Practice
350+ practice problems with step-by-step worked solutions covering dosage, dilutions, infusion rates, and unit conversions for the GPhC assessment.
One-time payment • Worked answers for every problem
Calculations are the #1 reason students fail the GPhC exam
Unit conversion errors, decimal mistakes, and time pressure cause even prepared students to lose marks. Our structured approach fixes this.
Everything You Need to Master Calculations
Dosage
85 problems
Weight-based, pediatric, geriatric
Dilutions
92 problems
Concentrations, molarity, %w/v
IV Rates
38 problems
Drip rates, infusion times
Alligation
42 problems
Mixture calculations
Plus unit conversions, pharmacokinetics, business calculations, and more
Try Free Calculations NowSee How Our Step-by-Step Method Works
Sample Question
A 70 kg patient needs digoxin 10 micrograms/kg. Stock is 250 micrograms/ml. What volume do you give?
Total dose
70 kg × 10 mcg/kg = 700 mcg
Volume needed
700 mcg ÷ 250 mcg/ml = 2.8 ml
Every question includes detailed explanations, common mistakes to avoid, and exam tips.
5 calculation questions included in free demo
Real Results from Real Students
“The step-by-step approach finally made calculations click for me.”
Aisha K.
Leeds
Calc score
45% → 89%
“Went from dreading calculations to finishing them with time to spare.”
Tom R.
Bristol
Calc score
52% → 85%
“The practice problems are exactly like the real exam.”
Fatima N.
Glasgow
Calc score
58% → 92%
Printable Formula Sheet Included
Every subscription includes a downloadable cheat sheet
Core Formulas
Dose = Weight × Dose per kg
Volume = Dose ÷ Concentration
C₁V₁ = C₂V₂ (dilutions)
Key Conversions
1 mg = 1000 micrograms
1 L = 1000 ml
1 pint = 568 ml
Less Than the Cost of One Resit
The GPhC exam costs £237. Our complete calculation practice costs a fraction of that.
One-time payment • No subscription
- 350+ calculation problems
- Step-by-step solutions
- Printable formula sheet
- Timed practice sessions
- Progress tracking
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Pharmaceutical Calculations — Frequently Asked Questions
What types of calculations are covered?
All nine CRA Part 1 calculation types: concentrations, dilutions, displacement volumes, dose and dosage regimens, infusion rates, medical statistics, pharmacoeconomics, pharmacokinetics, and quantities to supply. The library covers every calculation type listed in the GPhC 2026 framework.
How are calculations weighted in the CRA?
Part 1 of the Common Registration Assessment is dedicated to calculations: 40 free-numerical questions sat under timed conditions over 2 hours — about 3 minutes per question. Calculation accuracy is one of the highest-impact areas for first-attempt pass outcomes; the GPhC Board of Assessors has repeatedly flagged Part 1 errors (rounding, displacement volumes, infusion rates) as persistent failure patterns.
Are the worked solutions step-by-step?
Yes. Every calculation problem shows the full working — formula identification, unit conversion, the arithmetic step, and a sensibility check. Common mistakes (decimal placement, conversion errors, wrong formula choice) are flagged where relevant.
Can I use a calculator on the real CRA?
Yes. From 2026 the GPhC permits a calculator in both Part 1 and Part 2 — either a candidate's own model from the GPhC-approved list, or the Surpass on-screen calculator. This is a recent change; older guides describing Part 2 as no-calculator are out of date. The platform mirrors this.
Are calculations BNF and BNFC aligned?
Yes. Doses, formulations and concentrations reference current BNF and BNFC values. Where a question depends on a specific BNF or BNFC chapter (e.g. paediatric dosing in BNFC), the worked answer cites the chapter so you can cross-reference. The CRA samples from both BNF and BNFC.
Where do most candidates lose marks on calculations?
The Board of Assessors' June 2025 feedback specifically named rounding errors, displacement-volume mistakes, and IV infusion rate misinterpretation as persistent weak areas. None of those are content-knowledge problems — they're practice-volume problems. The platform tags these patterns in your performance analytics.