Checked against College Board, September 2026
AP Chemistry Exam Overview
A comprehensive guide to everything you need to know about the AP Chemistry exam, so you walk in confident and knowing exactly what to expect.
- 3h 15m
- Total testing time
- 60
- Multiple-choice questions
- 3
- Long free-response (10 pts each)
- 4
- Short free-response (4 pts each)
Exam timeline
3h 25m from the first question to the last. With check-in and instructions, budget close to four hours at school, and arrive at least 20 minutes early.
The main exam date is Thursday, May 6, 2027, 235 days from today. Start times vary by school, and there are alternate dates during the late-testing window.
Section I — Multiple Choice
1h 30m · 50% of your score60 questions
Either discrete questions or question sets, where you get a stimulus or a set of data and several questions built on it. Nothing is deducted for a wrong answer, so never leave one blank.
Break
about 10 minutesSupervised, between the two sections. With your proctor's permission you can leave the room for water or a snack, but you cannot leave the building, use a phone, or look at notes.
Section II — Free Response
1h 45m · 50% of your score7 questions, 46 points
3 long questions at 10 points each and 4 short ones at 4. Long questions are multi-part and usually mix a calculation with an explanation, so partial credit is very much in play — write something for every part.
Confirm your individual test date, location and start time with your AP coordinator.
Question styles
Section I is discrete questions plus question sets built on a shared stimulus or data set. Section II is written against six course skills, and long questions usually mix several in one problem.
- Models and representations
- Draw or interpret a model of what particles are doing.
- Question and method
- Design an experiment, or identify what a procedure is for.
- Representing data and phenomena
- Turn a description into a graph, table or diagram.
- Model analysis
- Explain why a model works, or where it breaks down.
- Mathematical routines
- Do the calculation, with units and a justified setup.
- Argumentation
- Make a claim and support it with evidence and reasoning.
What is allowed on the exam
The exam is administered through Bluebook, College Board's testing app. Bluebook carries a built-in Desmos scientific or graphing calculator, and gives you an equations sheet and a periodic table for both sections, so there is no need to memorize formulas, only to know how to apply them. The information on the reference sheet and periodic table can be viewed below.
These are Studyfor5's versions, covering the same reference information in our own styling rather than College Board's layout. The official PDFs are linked in the sources at the bottom of this page.
If you would rather use your own calculator, a scientific or graphing one is permitted on both sections and you can bring up to two approved models.
What each unit is worth
There are nine units in AP Chemistry. Units 3 and 8 are the most heavily weighted; the other seven are all weighted the same.
| Unit | Topics | Weighting | Section I questionsQuestions |
|---|---|---|---|
| Unit 1 Atomic Structure and Properties | 8 | 7-9% | 4-5 of 60 |
| Unit 2 Compound Structure and Properties | 7 | 7-9% | 4-5 of 60 |
| Unit 3 Properties of Substances and Mixtures | 13 | 18-22% | 11-13 of 60 |
| Unit 4 Chemical Reactions | 9 | 7-9% | 4-5 of 60 |
| Unit 5 Kinetics | 11 | 7-9% | 4-5 of 60 |
| Unit 6 Thermochemistry | 9 | 7-9% | 4-5 of 60 |
| Unit 7 Equilibrium | 12 | 7-9% | 4-5 of 60 |
| Unit 8 Acids and Bases | 11 | 11-15% | 7-9 of 60 |
| Unit 9 Thermodynamics and Electrochemistry | 11 | 7-9% | 4-5 of 60 |
Question counts are each unit's published weighting applied to the 60 multiple-choice questions, rounded. They are ranges because College Board publishes the weightings as ranges, and the exact split moves year to year.
2025 AP score distribution
College Board's own figures for the May 2025, worldwide administration. A 3 is the most common result, and 77.9% of students scored 3 or higher.
1
10,557
2
27,116
3
53,601
4
48,732
5
30,277
Each section is scaled to 50 points and added for a composite out of 100, which maps onto the 1 to 5 scale. The score calculator can help you understand what each score means, and work backwards to set a target for each section based on the score you are aiming for.
Before exam day
Your school is the authority on how your own exam runs, and they will tell you exactly what to bring. This is College Board's general list, and their prohibited list is worth reading properly, because a couple of the entries surprise people.
Bring
- Sharpened No. 2 pencils with erasers, and a pen with black or dark blue ink
- A fully charged testing device with Bluebook installed, plus its charging cable, unless your school provides one
- Up to two approved calculators — scientific or graphing
- A watch, as long as it is not a smartwatch
- A photo ID, if you are testing somewhere other than your own school
Not allowed in the room
- Mechanical pencils — ordinary No. 2 pencils only
- Colored pencils, stylus pens and protractors
- Smartwatches, fitness trackers and any other wearable
- Your own books, notes and scratch paper
Bring a snack and a bottle of water for the break. They cannot come into the exam room, but you will want them at the halfway point, and there is nowhere to buy anything once the administration has started.
The night before. Charge your device and have everything you need laid out. Sleep matters more than one last review pass at this point: the exam runs 3h 15m, and you want to be well-rested and feeling your best for it. Eat a healthy breakfast the morning of, wear comfortable clothing, and leave yourself plenty of time to get there.
Where to start
The course outline breaks all nine units into their individual topics. If you would rather find out where you stand first, the free diagnostic takes about half an hour and tells you which units to spend your time on, and the practice exams run the full thing under real timing, with every free-response answer graded against the rubric.
Common questions
What calculator can I use?
College Board lists a scientific or graphing calculator as permitted on both sections, and a built-in Desmos scientific or graphing calculator is available inside Bluebook. A four-function calculator is allowed but not recommended. You can bring up to two approved ones, and it is worth checking the current approved list before exam day because it changes.
Is there a penalty for guessing?
No. Nothing is deducted for a wrong answer and a blank scores exactly the same as a wrong one, so there is never a reason to leave a multiple-choice question unanswered. If you are running out of time, put something down for every remaining question.
What reference materials am I given?
College Board provides an equations sheet and reference tables, including the periodic table. You do not need to memorize what is on them, but the sheet tells you nothing about when to reach for a given equation, which is the part that actually earns points.
How is the exam scored?
Both sections count for exactly half. Each is scaled to 50 points and the two are added for a composite out of 100, which maps onto the 1 to 5 scale. Because the sections have different raw totals, one free-response point moves your composite further than one multiple-choice question does. Work out your own score.
How long is the exam, start to finish?
3h 15m of actual testing, plus a break of about 10 minutes between the sections. Check-in and instructions happen before any of that starts, so block out most of a half day rather than three and a quarter hours.
What is a good AP Chemistry score?
A 3 is conventionally called qualified, and 77.9% of students scored 3 or higher in May 2025. But College Board does not award your credit — each college sets its own policy and plenty want a 4 or a 5, so check the schools you are actually applying to rather than aiming at a general number.
Which units matter most?
Unit 3 is the single biggest at 18-22% of the exam, which is more than Units 1 and 2 put together, and Unit 8 is next at 11-15%. The other seven units are 7-9% each, so they are close to interchangeable in weight. The table above converts every weighting into question counts. See what each unit covers.
Sources
- AP Chemistry Exam — assessment overview — section structure, timing, weighting, and the long/short free-response point split
- AP Chemistry Student Score Distributions, May 2025 — score distribution, cohort size, and mean
- AP Chemistry equations and constants sheet (College Board PDF) — the official equations sheet provided during the exam
- AP Chemistry periodic table (College Board PDF) — the official periodic table provided during the exam
- AP Exam calculator policies — which calculators are permitted, and the approved list
- What to bring on AP Exam day — required and prohibited items
- AP Exam breaks policy — the scheduled break between sections and what is allowed during it
All College Board figures on this page were read from those documents and checked September 2026. Score percentages are College Board's own and do not total exactly 100, because each is rounded independently.