The semester grade for a specific course often includes a final exam and coursework completed prior to the exam. In this case, you can use a weighted average to calculate your final semester grade. A weighted grade average assigns a weight to different grade components. After calculating the weighted grade average, you can covert your percentage grade to a letter grade.

Determine the percentage score earned on the exam. For example, assume you scored 80 per cent on the exam.

Determine the per cent of the total grade the exam represents. For example, assume the exam represents 30 per cent of your total grade.

Determine your total percentage score prior to the exam. For example, assume that your total percentage score prior to the exam was 95 per cent.

Determine the per cent of your total grade that your percentage score before the exam accounts for. For example, you know your exam accounts for 30 per cent of the total grade. Subtract your exam grade from 100. Continuing the same example, 100 - 30 = 70 per cent.

Multiply your exam percentage score by the percentage of the grade your exam score represents. Continuing the same example, .80 x .30 = .24.

Multiply your percentage score before the exam by the percentage of your total grade this score represents. Continuing the same example, .95 x .70 = .665.

Add the figure from Step 5 to Step 6. Continuing the same example, .665 + .24 = 90.5 per cent.

Convert the percentage to a semester grade. Typically, a score higher than 90 per cent equals an A. A score between 80 per cent and 89.9 per cent equals a B. A score between 70 per cent and 79.9 per cent equals a C. A score between 60 per cent and 69.9 per cent equals a D, and a score lower than 60 per cent equals an F.