IB Economics Calculations SL And HL
Complete guide to IB Economics calculations required by the syllabus. Master elasticities, GDP, multipliers, and trade calculations for exam success
IB ECONOMICSIB ECONOMICS HLIB ECONOMICS SL
Lawrence Robert
11/27/20254 min read
IB Economics Calculations: Your Complete Syllabus Guide
Target question:
What calculations are required for IB Economics?
Secondary target questions:
What is Paper 3 in IB Economics HL?
How do you calculate PED in IB Economics?
What is the Keynesian multiplier formula?
One of the key skills in IB Economics is the ability to perform accurate calculations across different topics. The IB Economics syllabus specifies exactly which calculations you need to master, and they appear regularly in both IB Economics Paper 2 and IB Economics Paper 3 HL exams.
This comprehensive table maps out every calculation required by the syllabus, organised by section. You'll notice that calculations span all three modules of the course:
Microeconomics (Module 2) - From elasticities and market equilibrium to welfare loss and profit maximisation
Macroeconomics (Module 3) - Including GDP measures, inflation rates, and the Keynesian multiplier
Global / International Economics (Module 4) - Covering trade calculations, exchange rates, and balance of payments
Key formulas at a glance
PED = % change in Qd ÷ % change in P
PES = % change in Qs ÷ % change in P
YED = % change in Qd ÷ % change in income
GDP = C + I + G + (X − M)
Inflation rate = ((CPI₂ − CPI₁) ÷ CPI₁) × 100
Unemployment rate = (Unemployed ÷ Labour force) × 100
Keynesian multiplier = 1 ÷ (1 − MPC)
ΔY = multiplier × Δ(autonomous spending)
Real interest rate ≈ Nominal rate − Inflation rate
How to Use This Guide
Use this table as a checklist for your exam preparation. Each calculation listed here could appear in your exams - work through examples of each type until you can apply them confidently from data provided or from a diagram.
Pay particular attention to calculations that appear across multiple contexts: percentage changes underpin PED, PES, YED, inflation rates, and economic growth calculations. Mastering the percentage change calculation as a foundational skill makes every other formula more manageable.
For IB Economics HL students: Paper 3 tests these calculations directly from given datasets in a dedicated quantitative paper. IB Economics SL students encounter quantitative questions in Paper 2 as part of the data response. In both cases, the syllabus sections in the table below map precisely to what can be tested.
Exam tip - always show your working. Even if you know your final answer is incorrect, you can still earn method marks for demonstrating the correct approach. State the formula first, substitute values clearly, and show every intermediate step. A student who makes an arithmetic error but shows correct methodology earns more marks than one who writes only an answer without working.
How Calculations Are Assessed: Paper 2 vs Paper 3
Paper 2 (SL and HL - Data Response): quantitative questions appear within the data response context. You are given real economic data, a chart, or an extract and asked to calculate a specific value - the PED from a price and quantity table, the inflation rate from a CPI dataset, or a trade balance from export and import figures. The quantitative element is embedded within a broader analytical question.
Paper 3 (HL only - Quantitative Skills): this paper tests calculations directly and systematically. Every section of the syllabus that carries a calculation requirement in the table above can be tested in Paper 3. Questions are structured to isolate specific calculation skills - apply the formula, show the working, interpret the result. HL students should treat this table as their Paper 3 checklist: if a section appears here, it can and will be tested.
For worked examples of every calculation in this table, including model answers and marking schemes, see the IB Economics Calculations Book.
IB Economics Diagrams - What's included:
200+ exam-ready diagrams covering the entire IB Economics syllabus and some more
Video work showing you exactly each model with explanations
Image-ready versions perfect for answering essays, presentations, and your IA
Detailed written explanations of IB Economics theory next to each diagram
Both SL and HL diagrams clearly labelled and organised by module and unit
Real exam application showing how to use diagrams effectively in Paper 1 and Paper 2
Frequently Asked Questions - IB Economics Calculations
What calculations are required for IB Economics?
IB Economics requires calculations across Units 2, 3, and 4 of the 2022-26 syllabus. Unit 2 includes elasticity calculations (PED, PES, YED), consumer and producer surplus, welfare loss, tax revenue, and profit analysis. Unit 3 includes GDP and GNI, inflation rate (CPI), unemployment rate, real interest rates, Gini coefficient, and the Keynesian multiplier. Unit 4 includes exchange rate conversions, comparative advantage, balance of payments, and trade protection analysis. The table above maps every required calculation to its syllabus section reference.
What is the difference between Paper 2 and Paper 3 in IB Economics?
Paper 2 is a data response paper sat by both SL and HL students - quantitative questions appear within broader analytical responses to real economic data. Paper 3 is sat by HL students only and is dedicated to quantitative skills, testing calculations directly from given datasets with full working required. Every calculation in this table can appear in Paper 3.
What is the Keynesian multiplier formula in IB Economics?
The Keynesian multiplier is k = 1 ÷ (1 − MPC), where MPC is the marginal propensity to consume. It measures the total change in national income resulting from an initial change in autonomous spending: ΔY = multiplier × Δ(autonomous spending). With an MPC of 0.8, the multiplier is 5 - a £1 billion increase in government spending raises national income by £5 billion in total through successive rounds of spending.
How do you calculate PED in IB Economics?
PED = (% change in quantity demanded) ÷ (% change in price). Calculate each percentage change by dividing the change in the variable by its original value and multiplying by 100. A PED result greater than 1 in absolute terms indicates elastic demand; less than 1 indicates inelastic demand. Total revenue moves in the opposite direction to price when demand is elastic, and in the same direction when demand is inelastic.
How are method marks awarded in IB Economics calculation questions?
Method marks are awarded for demonstrating correct calculation methodology even when the final numerical answer is incorrect. Always state the formula first, substitute the values clearly, and show every intermediate step. A student who makes an arithmetic error but shows correct methodology earns more marks than one who writes only a final answer without working - this applies in both Paper 2 data response questions and Paper 3.
Explore Topics:
IB Economics - your IB Economics daily guide
IB Economics Introduction to Economics - access content related to IB Economics module 1
IB Economics Microeconomics - for accessing all microeconomics topics
IB Economics Macroeconomics - access all Macroeconomics calculations here as well as the rest of the module
IB Economics Activity book - for exam practice, activities, calculations, model answers and IB Economics Marking schemes
IB Economics Diagrams - Check diagrams with explanations covering the whole IB Economics course
IB Economics The Global Economy - access Calculations required for module 4 here as well as the rest of the module
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