Quick Answer: Your Top 6 average is calculated by taking your six highest Grade 12 U or M level course marks, always including the specific prerequisite courses required by your chosen program. Universities weight all six courses equally. There is no bonus for taking harder courses, and there is no penalty for having more than six Grade 12 U/M courses on your transcript. The computer system simply picks your six highest eligible marks, with mandatory prerequisites always included first. If a prerequisite is not one of your top six marks, it is still included, which pulls your average down. That is why course selection strategy matters.
Key Highlights of How to Calculate Your Top 6 Courses for Ontario University Admission
- Ontario universities calculate your admission average using exactly six Grade 12 U or M level courses, weighted equally
- Required program prerequisites are always included in your Top 6, even if they are not your highest marks
- You can include marks from online schools, night school, summer school, and private schools, as long as they are Ministry-recognized OSSD credits
- There is no advantage to taking more than six Grade 12 U/M courses, unless you use the extra courses to replace weaker marks
- Universities see all your Grade 11 and 12 marks on your transcript, but only calculate admission averages using the Top 6 formula
- Credit upgrading at a recognized private school can replace a weak mark in your Top 6 before universities finalize their decisions
What Are Grade 12 U and M Courses?
Ontario’s course coding system uses letters after the course number to indicate the type and pathway. The letter U stands for University Preparation, and the letter M stands for University and College Preparation. Both count toward your Top 6. Common examples include ENG4U (English, Grade 12, University), MHF4U (Advanced Functions, Grade 12, University), MCV4U (Calculus and Vectors), SCH4U (Chemistry), SBI4U (Biology), SPH4U (Physics), and BOH4M (Business Leadership, Grade 12, University/College). The 4 at the start means Grade 12.
Grade 12 C (College Preparation) and Grade 12 O (Open) courses do not count toward your Top 6 average. Neither do Grade 11 courses, regardless of level. Universities receive your full transcript with all marks, but only the Top 6 U/M courses at Grade 12 level enter the calculation. For a full explanation of what each course code means, read our guide on Ontario high school courses and the OSSD.
The Top 6 Calculation: How It Actually Works
Step 1: Identify all your Grade 12 U and M courses. Every course on your transcript with a 4U or 4M code is eligible. Count them up.
Step 2: Check which prerequisites your chosen program requires. ENG4U is required for almost every program. Engineering requires MHF4U and MCV4U (or sometimes just MHF4U). Sciences require combinations of SBI4U, SCH4U, and SPH4U. Business programs often require no specific courses beyond ENG4U, giving you more flexibility.
Step 3: Lock in your prerequisites. Those prerequisite marks are included in your Top 6 no matter what. If your ENG4U mark is 72% but your other marks are in the 80s and 90s, that 72% still counts and pulls your average down.
Step 4: Fill the remaining spots with your highest remaining U/M marks. After prerequisites are placed, the computer fills the remaining slots (usually 2 to 4 spots) with the highest Grade 12 U/M marks still available on your transcript.
Step 5: Average all six equally. Add the six marks together and divide by six. That is your admission average.
A Worked Example: Engineering at University of Waterloo
Waterloo Engineering typically requires: ENG4U, MHF4U, MCV4U, plus SCH4U or SPH4U (at least one). The remaining spots in your Top 6 are filled by your highest other U/M marks.
| Course | Mark | Role in Top 6 |
| ENG4U (English) | 78% | Mandatory prerequisite — included first |
| MHF4U (Advanced Functions) | 88% | Mandatory prerequisite |
| MCV4U (Calculus and Vectors) | 84% | Mandatory prerequisite |
| SCH4U (Chemistry) | 91% | Mandatory prerequisite (science) |
| SPH4U (Physics) | 85% | Highest remaining U/M mark |
| CGW4U (Geography) | 82% | Highest remaining U/M mark |
| Top 6 Average | 84.7% | (78+88+84+91+85+82) ÷ 6 |
Notice what happened with ENG4U in this example: even though it is the lowest mark in the Top 6, it cannot be dropped because it is a mandatory prerequisite for virtually all Ontario university programs. If this student had improved their English mark from 78% to 85%, their Top 6 average would have jumped from 84.7% to 85.8%. For competitive programs, that 1.1% gap is meaningful.
Top 6 Calculation for Different Program Types
Life Science Programs (Biology, Health Sciences, Pre-Med)
Required: ENG4U, SBI4U or SCH4U (often both). Top life science programs at McMaster, Queens, and UofT typically require both SBI4U and SCH4U, plus MHF4U or MDM4U for some programs. This means 3 to 4 of your 6 spots are already determined by prerequisites, and only 2 to 3 spots are filled by your best remaining marks.
Arts and Humanities Programs
Most arts programs only require ENG4U. That leaves 5 spots to fill with your five highest remaining U/M Grade 12 marks. This flexibility is a genuine advantage. Students applying to arts programs should deliberately choose their final Grade 12 electives to maximize their Top 6. A course like ETS4U (Studies in Literature), which many students find manageable, can contribute to your Top 6 if it is one of your stronger marks.
Business Programs (Commerce, BBA)
Business programs vary by school. Many require only ENG4U, though Schulich at York and Rotman at UofT often expect MHF4U or another math course for competitive applicants. Queens Commerce requires a math course. Waterloo’s AFM requires MHF4U or MDM4U. Always check the specific program requirements on the university’s website before planning your Grade 12 schedule. Our guide on OSSD business courses at USCA Academy covers the full list of business-related 4M and 4U courses available.
Courses That Count Toward Your Top 6: The Full List
Here is a non-exhaustive list of Grade 12 U and M courses that are eligible for your Top 6 calculation. Your actual transcript eligibility depends on whether the courses were taken at a recognized school:
| Code | Course Name | Subject Area |
| ENG4U | English | Compulsory — required by almost all programs |
| MHF4U | Advanced Functions | Mathematics |
| MCV4U | Calculus and Vectors | Mathematics |
| MDM4U | Mathematics of Data Management | Mathematics |
| SBI4U | Biology | Science |
| SCH4U | Chemistry | Science |
| SPH4U | Physics | Science |
| CGW4U | World Issues: A Geographic Analysis | Social Science |
| CHW4U | World History: The West and the World | Social Science |
| BOH4M | Business Leadership: Management Fundamentals | Business |
| BBB4M | International Business Fundamentals | Business |
| HHS4U | Families in Canada | Social Science |
| ETS4U | Studies in Literature | English |
| AVI4M | Visual Arts | Arts |
| HSB4U | Challenge and Change in Society | Social Science |
| CLN4U | Canadian and International Law | Social Science |
Can You Upgrade a Course to Improve Your Top 6?
Yes. If one of your current Grade 12 U/M marks is lower than you want, you can retake the course at a recognized private school, night school, or online school. The new mark replaces the old mark in your transcript for OUAC purposes. This is one of the most effective ways to improve your Top 6 average before university decisions are finalized. USCA Academy offers credit course upgrades on a flexible schedule that allows students to complete or upgrade credits at times that work around their regular school schedule. Our credit courses in Mississauga are available for all major Grade 12 U and M subjects.
The most impactful upgrade is almost always your lowest-mark prerequisite. Because prerequisites cannot be dropped from your Top 6, a low mark there hurts more than a low mark in an optional course. If your ENG4U mark is 72% and your other marks are 85%, upgrading ENG4U to 82% adds 10 percentage points to your total and raises your average by 1.67%. Our guide on how to raise your Grade 12 average before university cutoffs explains the full credit upgrade process and timeline.
Does Your Top 6 Change After Conditional Offers?
When Ontario universities make conditional offers in February and March, they are based on your mid-year marks (Semester 1 finals or Term 1 averages). After your final June exams, OUAC sends your updated marks to universities. If your final Top 6 average drops significantly below your conditional offer average, your offer may be rescinded. Keeping your marks strong through the full year matters. For a detailed breakdown of what happens after you receive a conditional offer and how final marks are assessed, read our guide on the Ontario university conditional offer process.
Common Top 6 Mistakes Ontario Students Make
- Not checking prerequisites before choosing Grade 12 courses: Discovering in January that you are missing a required prerequisite for your program leaves no time to fix it
- Taking too many hard courses: ENG4U, MHF4U, MCV4U, SCH4U, SBI4U, and SPH4U all in one semester can spread you too thin and lower all your marks
- Assuming a C or O course will count: Only U and M courses count toward the Top 6
- Ignoring Grade 12 electives as Top 6 opportunities: A well-chosen elective where you are confident of a strong mark can replace a weaker science or math mark in your Top 6
- Not upgrading a low prerequisite mark: If ENG4U is pulling your average down, upgrading it is usually the highest-return action available
| Need to upgrade a Grade 12 course to strengthen your Top 6? USCA Academy offers Ministry-inspected credit courses in all major Grade 12 U and M subjects with flexible scheduling. Call +1 (905) 232-0411 or visit uscaacademy.com/credit-courses to find the course you need. |
Frequently Asked Questions About Top 6 Courses Ontario
1. Can I include online OSSD courses in my Top 6?
Yes. Any Grade 12 U or M course from a Ministry-recognized school counts toward your Top 6, whether it was taken in a traditional classroom, at a private school, online, or through night school. USCA Academy is Ministry-inspected, which means credits earned here are fully recognized for OUAC applications. You can read more about online credit options at our online high school courses in Ontario page.
2. Do universities see marks from all your Grade 12 courses, or just the Top 6?
Universities receive your full OSSD transcript, which shows all Grade 11 and 12 marks. They see everything. The Top 6 is the formula used to calculate your numeric admission average, but some universities and programs look at your broader transcript for supplementary applications and scholarship decisions. A very low mark in a relevant course can raise questions even if it is not in your Top 6. This is another reason why upgrading weak marks makes sense. For more on how universities evaluate your OUAC application holistically, read our OUAC 101 guide.
3. What if I have more than six Grade 12 U/M courses?
Having extra Grade 12 U/M courses is never a disadvantage. The Top 6 calculation always takes your six highest eligible marks (with prerequisites included first). Extra courses give you more options. A student who takes eight Grade 12 U/M courses has the two weakest marks automatically excluded from the Top 6 calculation, which is purely beneficial if those extra courses are not prerequisites.
4. What is the difference between Top 6 and admission average?
These terms mean the same thing in Ontario. Your admission average is your Top 6 average. Some sources also call it your overall average. When a university lists its minimum admission average or its competitive average for a program, they are referring to the Top 6 calculation described in this guide. For an overview of the admission average ranges for specific Ontario university programs, see our guide on how to calculate your Ontario university admission average.
