Average, weighted average and median
Type your numbers and the calculator gives their average at once, along with the median, the number of values, the lowest and the highest. Tap + Add for each new value, or press Enter in the last box. When some values count more than others, as with grades in a course or prices bought in different quantities, switch to the weighted average.
The simple average (mean)
Add up the values and divide by how many there are. For 12, 15, 9 and 14: (12 + 15 + 9 + 14) ÷ 4 = 50 ÷ 4 = 12.5. The line under the result shows that sum, so you can check it. This is what most people mean by “the average”: average spending per month, average temperature over a week, average score of a team.
The weighted average
In a weighted average, each value is multiplied by its weight, and the total is divided by the sum of the weights. With the same four values and weights of 1, 2, 1 and 1: (12 × 1 + 15 × 2 + 9 × 1 + 14 × 1) ÷ 5 = (12 + 30 + 9 + 14) ÷ 5 = 65 ÷ 5 = 13. The 15 counts twice, so it pulls the average up.
Weights can be anything that says how much a value counts: a number of credits, a share of the final grade, a quantity. A course where homework counts for 20%, the midterm for 30% and the final exam for 50%: with scores of 92, 78 and 85, the weighted average is (92 × 20 + 78 × 30 + 85 × 50) ÷ 100 = 84.3. Type the percentages as weights; they do not need to add up to 100, the calculator divides by their total anyway.
Grades and GPA
In the United States, a GPA (grade point average) is a weighted average of grade points, with each course’s credit hours as weights. Grade points are set by each school, so check your school’s own scale before you convert letters into numbers. Once you have them, type each course’s points as a value and its credits as the weight. For example, points of 3.7, 3.0, 4.0 and 3.3 for courses of 4, 3, 3 and 2 credits give a weighted average of 3.53.
The median
The median is the middle value once the values are sorted: half are below, half above. With an even number of values, it is halfway between the two in the middle. For 9, 12, 14 and 15, the median is (12 + 14) ÷ 2 = 13. The median is not pulled by an extreme value. Five salaries of $40,000 and one of $400,000 have an average of $100,000, which describes nobody, but a median of $40,000. When the average and the median are far apart, a few unusual values are probably weighing on the result.
Tips
- Lowest and highest. The range, from the lowest to the highest value, shows how spread out your values are. Two classes can have the same average and very different ranges.
- Negative numbers and decimals are fine. Empty boxes are ignored.
- Averaging percentages. Be careful when the groups are not the same size: 80% of 10 people and 60% of 40 people is not a 70% average. Use the group sizes as weights: (80 × 10 + 60 × 40) ÷ 50 = 64%.
- Voice. Tap the microphone and say “average of 12, 15 and 9”: the boxes fill in by themselves.
- Percentages. To turn a score like 42 out of 50 into a percentage first, use the percentage calculator; to rescale a mark to another total, the proportion calculator does it in one step.
Your values and the number of boxes are kept in your browser, so they are still there next time. Copy result copies the average, and Share gives a link that reopens the same list. For essays and reports that are graded by length, the word counter tells you where you stand.