How To Find Out What Two Grades Will Average Out To

Most teachers will give you periodic updates on your grades throughout the year, letting you know what your final grade would be if the class ended right then and there. But you can figure the same information for yourself by finding the average of two or more grades or, to use the proper statistical term, the mean value. There's just one catch: The grades have to be in number form.

Often, you'll receive your grades as percentages. Let's say you scored 90 percent on one test, but struggled on the other and got a score of 72 percent. To average the two scores, first add them together: 72 + 90 = 162 percent. Next, divide that result by the number of scores involved (in this case, two) to get the mean value or average: 162 ÷ 2 = 81 percent. Note that you must carry the unit of measure over through every step of the calculation. Otherwise, you won't know how to interpret the result.

You can find the average of two letter grades, too, as long as you convert them into numbers first. The following, long-established system assigns a point value to each letter grade:

•A = 4 points
•B = 3 points
•C = 2 points
•D = 1 point
•F = 0 points

So if you had an A in one class and a B in one class, you'd convert that to 4 points (for the A) and 3 points (for the B). Then do the same calculation as for averaging any other number grade. First, add the two grade values together: 4 + 3 = 7 points. Then divide by the number of grades in the calculation (in this case, two). That leaves you with 7 ÷ 2 = 3.5 points as your average score. Some systems would convert that into a B+ or A-, but usually these points-for-grades scores, also known as your grade point average, are simply left in points form.

You can use the same formula to calculator the mean value of more than two scores. Simply add all the scores together, then divide by the number of scores you used.

\(\text{Average score} = \frac{\text{Sum of all scores}}{\text{Number of scores}}\)

So if you took four tests throughout the year, getting 78, 93, 84 and 89 percent as your scores, first add them together: 78 + 93 + 84 + 89 = 344 percent. Then divide by the number of scores you used (in this case, four) to find your average or mean score: 344 ÷ 4 = 86 percent.