Medical school prerequisites are the specific undergraduate courses and credit hours that most U.S. and Canadian medical schools require before enrollment. They typically cover biology, chemistry, organic chemistry, physics, and mathematics, with many schools adding biochemistry, social sciences, and humanities. Getting these right early protects your GPA, keeps your application eligible, and prevents a last-minute scramble during application season.
This guide breaks down the standard requirements, the credits each course usually carries, the schools that deviate from the norm, and how to plan a four-year schedule that satisfies every prerequisite without overloading yourself. It also covers the questions that trip up even well-prepared applicants: whether you can apply before finishing, how AP and community college credit are treated, and what to do when two schools on your list contradict each other.
What “Prerequisites” Actually Means for Medical School
Prerequisites are not a suggestion. They are admission requirements. If you do not complete them, your application can be screened out before a human ever reads your personal statement.
There are two layers to understand. The first is coursework: the subjects you must study. The second is credit hours: how much of each subject you must complete. Both matter, and schools check both.
Most medical schools in the United States and Canada expect applicants to finish prerequisites before matriculation, not before applying. That means you can apply while still completing a required course, as long as it will be done before you start medical school.
However, some schools require prerequisites to be completed before you submit your application. Always confirm the policy at each school on your list, because the rules vary more than most students expect.
The Core Prerequisite Courses Most Schools Require
The vast majority of medical schools require the same foundational set. These are the courses that appear on nearly every prerequisite list.
- General Biology with lab — one full year, typically 8 semester credits
- General Chemistry with lab — one full year, typically 8 semester credits
- Organic Chemistry with lab — one full year, typically 8 semester credits
- General Physics with lab — one full year, typically 8 semester credits
- Mathematics — usually one year, covering calculus and/or statistics
- English — one year of composition or writing-intensive coursework
These six areas form the backbone of nearly every prerequisite list. If you complete them with strong grades, you keep the widest possible range of schools open to you.
General Biology
Biology is the most universal prerequisite. Almost every medical school requires a full year with laboratory work.
Some schools accept a combination of introductory biology and upper-level biology courses. Others want specifically the introductory sequence. Check the wording carefully, because “one year of biology” can mean different things at different institutions.
General Chemistry
General chemistry is required almost everywhere, and it is usually a prerequisite for organic chemistry. This means you cannot delay it without delaying everything that follows.
Most students take general chemistry in their first year. Doing so keeps the sequence on track and avoids a crowded junior year.
Organic Chemistry
Organic chemistry carries a reputation for difficulty, and it is required by most medical schools. A full year with lab is the standard expectation.
Some schools have reduced or dropped the organic chemistry requirement in recent years, often replacing it with biochemistry. This is a real trend, but it is not universal, so verify each school individually.
General Physics
Physics is required by most schools, usually one full year with lab. Algebra-based physics is generally accepted, though some schools prefer calculus-based.
If you are choosing between the two, algebra-based physics is usually the safer option for prerequisite purposes unless a specific school states otherwise.
Mathematics
Math requirements vary more than any other subject. Some schools want one year of calculus. Others accept statistics, or a combination of calculus and statistics.
Statistics is increasingly valuable because it supports research and data interpretation in medicine. Taking both calculus and statistics keeps the most doors open.
English and Writing
Most schools require one year of English or writing-intensive coursework. This is often the easiest requirement to satisfy, and it is frequently overlooked until late.
Any writing-heavy humanities course may count at some schools. Confirm the exact wording, because “English” and “writing-intensive” are not interchangeable everywhere.
Prerequisite Credits: How Many You Actually Need
Credit requirements are where students get confused. The number of credits depends on your school’s system and on how each medical school counts coursework.
Most requirements are expressed as “one year” or “two semesters” rather than a specific number. On a semester system, one year usually equals 6 to 8 credits. On a quarter system, it usually equals 9 to 12 credits.
Below is a practical reference table for the most common prerequisites.
| Prerequisite | Typical Duration | Semester Credits | Quarter Credits |
|---|---|---|---|
| General Biology with lab | 1 year | 8 | 12 |
| General Chemistry with lab | 1 year | 8 | 12 |
| Organic Chemistry with lab | 1 year | 8 | 12 |
| General Physics with lab | 1 year | 8 | 12 |
| Mathematics | 1 year | 6–8 | 9–12 |
| English / Writing | 1 year | 6 | 9 |
| Biochemistry | 1 semester | 3–4 | 4–6 |
These numbers are typical, not universal. Some schools specify a minimum credit count, while others simply say “one academic year.”
If your school uses a quarter system, be especially careful. A course that covers one quarter is not the same as a course that covers one semester, and medical schools know the difference. A single quarter of organic chemistry will not satisfy a school that asks for a full year, even if the course title sounds equivalent.
Beyond the Basics: Additional Requirements Many Schools Add
The core six subjects are not the whole picture. A growing number of schools require or strongly recommend additional coursework.
- Biochemistry — now required by many schools, often one semester
- Statistics — increasingly expected for research literacy
- Psychology — required or recommended for understanding behavior
- Sociology — often paired with psychology as a social science requirement
- Genetics — required at some schools, recommended at others
- Humanities — ethics, philosophy, or literature courses at some programs
These additions reflect how medicine has changed. Schools want applicants who understand data, human behavior, and the ethical dimensions of care.
Biochemistry
Biochemistry has become one of the most commonly added requirements. It bridges biology and chemistry and underpins much of modern medical science.
Many schools now require one semester of biochemistry, and some accept it in place of part of the organic chemistry requirement. Read each school’s policy carefully before assuming either course can substitute for the other.
Social and Behavioral Sciences
Psychology and sociology appear on a large number of prerequisite lists. Some schools require both, while others accept either.
These courses also help prepare you for the social and behavioral science content on the MCAT, so they serve double duty.
Statistics and Data Skills
Statistics is not always listed as a hard requirement, but it is increasingly valued. It supports research participation and helps you interpret medical literature.
If you have room in your schedule, taking statistics is a low-risk, high-reward choice.
How Prerequisites Differ Between U.S. and Canadian Schools
U.S. and Canadian medical schools share many requirements, but there are meaningful differences.
In the United States, requirements vary widely by school. Some programs have trimmed their lists, while others remain traditional.
In Canada, requirements also vary by province and institution. Some Canadian schools place heavy weight on specific courses and credit counts, and a few have unusual policies about which courses count.
- U.S. schools often express requirements as “one year” of a subject
- Canadian schools may specify exact course codes or credit minimums
- Some Canadian schools require specific upper-level courses
- Both countries generally require lab work for science prerequisites
- Both generally accept community college coursework, with conditions
If you are applying to both countries, build your plan around the strictest set of requirements you can find. That approach keeps every option open.
Community College, AP, and Transfer Credits
Students frequently ask whether non-traditional coursework counts. The answer depends on the school and the course.
Many medical schools accept community college prerequisites, especially for introductory courses. Others prefer that science prerequisites be taken at a four-year institution.
Advanced Placement credit is trickier. Some schools accept AP credit to satisfy prerequisites, while others require you to take the college-level course regardless.
- Community college science courses are accepted by many, but not all, schools
- AP credit may satisfy some requirements but often needs a higher-level course as backup
- Online lab courses are accepted by some schools and rejected by others
- Pass/fail grades are usually discouraged for prerequisites
- Transfer credits must appear on an official transcript
The safest strategy is to take prerequisites for a letter grade at a four-year institution whenever possible. If you use AP or community college credit, confirm acceptance in writing with each school.
Grades Matter as Much as Completion
Finishing a prerequisite is not enough. Medical schools look closely at the grades you earned in those courses.
Science prerequisites are often grouped into a science GPA, sometimes called a BCPM GPA, which covers biology, chemistry, physics, and math. This number is reviewed separately from your overall GPA.
A strong overall GPA with weak science grades raises concerns. A solid science GPA with a slightly lower overall GPA is usually less problematic.
- Aim for strong grades in every prerequisite, not just a passing mark
- Retaking a course may be allowed, but policies vary by school
- Grade replacement is handled differently across application systems
- Upward trends in grades can work in your favor
- Consistent performance across all science courses is ideal
Building a Four-Year Plan That Fits
Prerequisites have a natural order. Chemistry comes before organic chemistry, and biology often supports upper-level courses. Planning around that order prevents scheduling conflicts.
A typical sequence looks like this:
- Year one: General biology, general chemistry, English, math
- Year two: Organic chemistry, physics, statistics, social science
- Year three: Biochemistry, upper-level biology, remaining humanities
- Year four: Finish any gaps, complete your major, prepare applications
This is a template, not a rule. Some students spread prerequisites across more time, and others compress them. What matters is that you complete them before matriculation and keep your grades strong.
Balancing Prerequisites With Your Major
You do not need to major in biology or chemistry. Medical schools accept any major as long as prerequisites are complete.
In fact, majoring in something you genuinely enjoy can make you a more interesting applicant. Just make sure your major and prerequisites do not collide in a way that forces you to overload every semester.
When to Take the MCAT
The MCAT tests content from your prerequisites, especially biology, chemistry, physics, biochemistry, and psychology or sociology. Taking it after completing those courses usually leads to a better score.
Most students take the MCAT in the spring or summer before their application year. Plan your prerequisite schedule so the relevant courses are done by then.
Common Mistakes to Avoid
Small planning errors can create large problems later. These are the mistakes that come up most often.
- Assuming all medical schools have identical requirements
- Delaying chemistry and falling behind the sequence
- Taking prerequisites pass/fail without checking school policy
- Ignoring lab requirements when selecting courses
- Forgetting that some schools require prerequisites before applying
- Relying on AP credit without confirming acceptance
- Neglecting English and writing requirements until senior year
- Choosing a major that leaves no room for prerequisites
Avoiding these mistakes is mostly about verifying requirements early and planning backward from your application timeline.
How to Verify Requirements for Your Target Schools
Requirements change, and no general guide can replace the official source. Always confirm details directly.
- Check each school’s official admissions website
- Look for a dedicated “prerequisites” or “admission requirements” page
- Review the current application cycle requirements, not older guides
- Contact admissions directly when wording is unclear
- Keep a spreadsheet tracking requirements for every school on your list
A tracking spreadsheet is one of the most useful tools you can build. List each school, each required course, the credits needed, and your completion status.
Requirements can change from one application cycle to the next. Treat any general guide, including this one, as a starting point and confirm every detail with the schools you plan to apply to.
Conclusion
Medical school prerequisites are predictable once you understand the pattern. A year each of biology, general chemistry, organic chemistry, and physics, plus math and English, covers the foundation at most schools. Many programs add biochemistry, statistics, and social sciences on top of that.
The credit hours matter as much as the subjects, and the grades matter as much as the completion. Plan your courses early, verify requirements with each school, and keep your options open by meeting the strictest standards you can find. Done thoughtfully, prerequisites become a manageable checklist rather than a source of stress.
Frequently Asked Questions
What are the most common medical school prerequisites?
The most common prerequisites are one year each of general biology, general chemistry, organic chemistry, and general physics, all with lab work. Most schools also require one year of mathematics and one year of English or writing-intensive coursework. Many schools add biochemistry, statistics, psychology, or sociology to that list.
How many credits do medical school prerequisites usually require?
On a semester system, each one-year science prerequisite typically equals 8 credits, and math or English usually equals 6 credits. On a quarter system, the same courses usually equal 9 to 12 credits. Most schools express requirements as “one year” rather than an exact credit number, but the credit count still matters when verifying eligibility.
Do all medical schools require the same prerequisites?
No. While the core science requirements are widely shared, schools differ in how many courses they require and which additional subjects they add. Some schools have reduced organic chemistry requirements and added biochemistry, while others remain traditional. Always check each school’s official admissions page.
Can I apply before finishing all my prerequisites?
In most cases, yes. Many schools allow you to apply while completing prerequisites, as long as you finish them before matriculation. However, some schools require prerequisites to be complete before you submit your application. Confirm the policy at every school on your list.
Does biochemistry count as a medical school prerequisite?
At many schools, yes. Biochemistry has become one of the most commonly required additional courses, usually one semester. Some schools accept it in place of part of the organic chemistry requirement, but this varies, so check each school’s specific policy before assuming a substitution is allowed.
Are community college prerequisites accepted by medical schools?
Many medical schools accept community college coursework for prerequisites, particularly introductory courses. Others prefer that science prerequisites be taken at a four-year institution. If you plan to use community college credits, confirm acceptance with each school in advance.
Can AP credit satisfy medical school prerequisites?
Some schools accept Advanced Placement credit toward prerequisites, while others require you to take the college-level course regardless of your AP score. Even when AP credit is accepted, a higher-level college course in the same subject is often recommended as a safer path.
What grades do I need in prerequisite courses?
There is no universal minimum, but competitive applicants generally earn strong grades, often in the A or B range. Prerequisite grades feed into a science GPA that admissions committees review separately. A passing grade alone is usually not enough to be competitive.
Do prerequisites have to be taken in a specific order?
Some do. General chemistry is usually a prerequisite for organic chemistry, and biology often supports upper-level courses. Beyond those natural sequences, you have flexibility. Planning around the required order prevents scheduling conflicts later.
Do I need to major in a science to meet prerequisites?
No. Medical schools accept any major as long as you complete the required prerequisites. Many successful applicants major in humanities, social sciences, or other fields and simply complete the science requirements alongside their major.
