Determine how your particular class weights lecture grades and lab grades. Many times your lab grade will count for 25 percent of your final score, as it is one credit hour and the course itself is three credit hours.
Calculate your total lab grade by adding all of your individual grades together and dividing by the total number.
Calculate your total lecture grade by adding all of your individual grades together and dividing by the total number.
Multiply your lab grade by the percentage it counts towards, such as 0.25 for 25 percent.
Multiply your lecture grade by the percentage it counts towards your grade, such as 0.75 for 75 percent.
Add the two numbers together to get the total grade. This gives you the total percentage, allowing you to determine your letter grade.
Determine the way your grade is calculated from your syllabus. This is often the same as the percentage, but instructors might give total numbers for both lecture and lab. In this case, grades for each assignment may be assigned a number instead of a percentage score.
Add up the total number of points you have earned in your lab class.
Calculate the total number of points you have earned in your lecture section. Add this number to the total you received for the lab portion.
Divide the total you earned by the total number of points possible in the course in order to determine your percentage grade. This will translate to your letter grade.