How GPA is calculated
GPA = Σ (grade points × credit hours) ÷ Σ (credit hours). Each letter grade has a numeric value (e.g. A+ = 4.0 on the 4.0 scale, 4.3 on the 4.3 scale); each course has a credit-hour weight (typically 3 credits for a standard semester course, 6 for a full-year course). Multiply, sum, divide. The result is your weighted average — a 6-credit course counts twice as much as a 3-credit course.
Why scales differ
The 4.3 scale rewards A+ grades with extra points beyond a flat A. The 4.0 scale caps at 4.0, so an A+ and an A both count as 4.0 toward GPA. This means a student with mostly A+ grades will look stronger on a 4.3 transcript than the same record converted to 4.0. Most Ontario professional schools (medicine, law) use OMSAS’s own conversion to standardize across institutions.
For a precise number
Your registrar’s official transcript is the source of truth. This calculator approximates the math but doesn’t handle: pass/fail courses, withdrawals, course retakes (where some schools replace the original grade and others average), or programme-specific weightings (some programmes weight major courses more heavily). For graduate school applications, always send the official transcript — adcoms calculate their own GPAs from those.