The Most-Tested IGCSE Topics (2026 Report): What 107,200 Real Exam Questions Reveal
The single most-tested IGCSE topic in our entire question bank is Properties of Acids & Bases (Chemistry 0620), with 1,231 tagged past-paper questions — and the pattern it sits on top of is the most useful fact in revision: in every IGCSE subject we analysed, the top 10 topics account for roughly a quarter of all exam questions ever asked (and in ICT, over a third). This report ranks those topics, subject by subject, from an analysis of 107,200 real Cambridge and Edexcel exam questions — so you can spend your revision hours where the examiners actually spend their marks.
- Chemistry 0620: Acids & Bases, Air, and Writing Equations dominate — the top 10 topics carry 24% of 34,597 questions.
- Maths 0580: Basic Probability is the most-tested topic (781 questions), ahead of Mean/Median/Mode and Types of Numbers.
- Physics 0625: Mass & Weight and Atomic structure (Protons, Neutrons & Electrons) lead — 25% of questions sit in the top 10.
- Economics 0455 is the most concentrated theory subject: 27% of all questions come from just 10 topics.
- ICT 0417 is the most predictable of all: the top 10 topics = 37% of every question asked.
- Strategy: master your subject's top 10 first, at past-paper level — then spread out.
Chemistry 0620 — 34,597 questions
| # | Topic | Questions |
|---|---|---|
| 1 | Properties of Acids & Bases | 1,231 |
| 2 | Air | 1,154 |
| 3 | Writing Equations | 971 |
| 4 | Atomic Structure | 795 |
| 5 | Alcohols | 725 |
| 6 | Fossil Fuels | 723 |
| 7 | Separation & Purification Techniques | 711 |
| 8 | Oxidation & Reduction | 697 |
| 9 | Rates of Reaction Factors | 685 |
| 10 | Reactivity Series | 674 |
Top 10 = 8,366 questions — 24.2% of everything ever asked in 0620. Full breakdown: the Chemistry most-tested deep-dive.
Mathematics 0580 — 27,128 questions
| # | Topic | Questions |
|---|---|---|
| 1 | Basic Probability | 781 |
| 2 | Mean, Median & Mode | 675 |
| 3 | Types of Numbers | 590 |
| 4 | Laws of Indices | 571 |
| 5 | Powers & Roots | 535 |
| 6 | Solving Linear Equations | 535 |
| 7 | nth Terms of Linear Sequences | 531 |
| 8 | Introduction to Sequences | 522 |
| 9 | Time | 506 |
| 10 | Volume | 499 |
Top 10 = 5,745 questions — 21.2% of 0580. Full breakdown: the Maths most-tested deep-dive.
Economics 0455 — 14,418 questions
| # | Topic | Questions |
|---|---|---|
| 1 | Indicators of Living Standards | 533 |
| 2 | Costs & Revenue | 520 |
| 3 | Protection | 429 |
| 4 | Spending, Saving & Borrowing | 397 |
| 5 | Taxation | 382 |
| 6 | Effects of Changing Population Sizes | 354 |
| 7 | Opportunity Cost in Decision Making | 337 |
| 8 | The Factors & Their Rewards | 336 |
| 9 | Causes & Consequences (Inflation) | 325 |
| 10 | The Growth of Firms | 315 |
Top 10 = 3,928 questions — 27.2% of 0455, the most concentrated theory subject. Full breakdown: the Economics most-tested deep-dive.
Physics 0625 — 12,963 questions
| # | Topic | Questions |
|---|---|---|
| 1 | Mass & Weight | 455 |
| 2 | Protons, Neutrons & Electrons | 451 |
| 3 | Sound Waves | 393 |
| 4 | Thermal Expansion | 314 |
| 5 | Electrical Safety | 289 |
| 6 | Magnets | 282 |
| 7 | Half-Life | 278 |
| 8 | Measurement | 273 |
| 9 | Particle Model of Gases | 263 |
| 10 | Electromagnetic Waves | 258 |
Top 10 = 3,256 questions — 25.1% of 0625. Full breakdown: the Physics most-tested deep-dive.
ICT 0417 — 7,046 questions
| # | Topic | Questions |
|---|---|---|
| 1 | Input Devices | 408 |
| 2 | Types of Database | 352 |
| 3 | Storage | 294 |
| 4 | The Internet | 255 |
| 5 | Output Devices | 252 |
| 6 | Software | 235 |
| 7 | Formulae & Functions | 214 |
| 8 | Computer Controlled Systems | 198 |
| 9 | Microprocessor-Controlled Devices | 195 |
| 10 | The Systems Life Cycle: Testing | 184 |
Top 10 = 2,587 questions — 36.7% of 0417, the most predictable subject in this report. Full breakdown: the ICT most-tested deep-dive.
Biology 0610 — 5,691 questions
| # | Topic | Questions |
|---|---|---|
| 1 | Monohybrid Inheritance | 181 |
| 2 | Sexual Reproduction in Humans | 180 |
| 3 | Sexual Reproduction in Plants | 175 |
| 4 | Diet & Deficiencies | 168 |
| 5 | Genetic Modification | 126 |
| 6 | Characteristics of Living Organisms | 121 |
| 7 | Anaerobic Respiration | 111 |
| 8 | Food Chains & Food Webs | 103 |
| 9 | Drugs in Medicine | 101 |
| 10 | Nutrient Cycles | 93 |
Top 10 = 1,359 questions — 23.9% of 0610. Full breakdown: the Biology most-tested deep-dive.
Business 0450 — 5,357 questions
| # | Topic | Questions |
|---|---|---|
| 1 | The Main Types of Ownership | 197 |
| 2 | The Main Production Methods | 138 |
| 3 | Promotion | 134 |
| 4 | Different Types of Costs | 130 |
| 5 | Environmental Concerns: Externalities | 126 |
| 6 | Statement of Financial Position | 115 |
| 7 | Organisational Charts & Roles | 114 |
| 8 | Types of Pricing Methods | 112 |
| 9 | Types of Communication Methods | 112 |
| 10 | Using Cash-Flow Forecasts | 111 |
Top 10 = 1,289 questions — 24.1% of 0450. Full breakdown: the Business most-tested deep-dive.
What the numbers actually tell you
- Concentration is real, and consistent. Five of seven subjects cluster between 21% and 27% for their top 10 — examiners return to the same wells year after year, because the syllabus weights them that way.
- ICT is the outlier (36.7%). If you're taking 0417, a disproportionate share of your paper is drawn from ten topics. Drill them to automaticity.
- "Most-tested" ≠ "hardest." These are the highest-volume topics, which makes them the highest-return revision — but they're often tested at every difficulty level, from 1-mark recall to 6-mark extended answers. Practising them at past-paper level, against the real mark scheme, is what converts familiarity into marks.
- Don't invert the lesson. The other ~75% of questions still exist. The play is sequencing — top 10 first and deepest, then coverage — not exclusivity. Build it into your revision timetable.
FAQ
What are the most-tested IGCSE topics?
How much of the exam comes from the top 10 topics?
Where does this data come from?
Should I only revise the most-tested topics?
Examiners are more predictable than students think — not because papers repeat, but because syllabuses weight what matters. Now you know where the weight is. Open your subject's #1 topic, answer its real questions, and let the marking tell you what to fix.
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