---
title: "GPhC Calculations | Worked Questions & Formulas | PharmX"
description: "GPhC calculations practice with step-by-step worked examples: doses, dilutions, infusion rates and concentrations — built for the registration assessment."
url: https://pharmx.co.uk/calculations
site: PharmX
publisher: PharmX
locale: en-GB
retrieved: 2026-08-28
---
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# Get every mark you deserve in calculations

Step-by-step methods for doses, dilutions, infusions and more, built for GPhC exam accuracy. Master the formulas and techniques that matter most.

 Exam Structure

 40 Questions

 120 minutes | 3 minutes per question

 Calculator and numerical entry format

 Unit Conversions

 1 kg = 1000 grams

 1 gram = 1000 milligrams

 1 milligram = 1000 micrograms

 Rounding Rules

 Give your answer to the nearest 0.05 mL

 Round up to the nearest 15 mg

 Give your answer to one decimal place

 Key Formulas

 M = 1 mole of solute in 1L (1000ml)

 1 kg = 2.2 lb

 10% w/w: 10g solute in 100g

## How PharmX Makes Calculations Click

 Calculate required dose

 25mg × 4.2 = 105mg

 Reconstitution Volume

 6mL + 0.3mL = 6.3mL

 So, 300mg in 6.3 mL

 300mg → 6.3 mL

 105mg → X

 (105 × 6.3) / 300

 = 2.205 mL

 = 2.2 mL

 to one decimal place

### Extensive Practice

Work through hundreds of calculations step-by-step with immediate feedback.

### Conversion Excellence

Master rounding and unit conversions with step-by-step guidance.

### Instant Validation

Get immediate confirmation with detailed explanations for every answer.

## What's Covered

 🧪

### Concentrations

 💧

### Dilutions

 ⚖️

### Displacement Volumes

 💊

### Dose and Dosage Regimens

 💉

### Infusion Rates

 📊

### Medical Statistics

 💰

### Pharmacoeconomics

 ⏱️

### Pharmacokinetics

 📦

### Quantities to Supply

## Calculations
 Success

The calculations training that helped so many trainees score **35+** in the June 2026 CRA exam.

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