Frequently Asked Questions

Yes, the weighted mean is the same as the weighted average. Statistics prefers the term weighted arithmetic mean, academic grading prefers weighted average, and both terms name the sum of weighted values divided by the sum of weights.

Yes, weights can be decimals. Probabilities of 0.25 and 0.75, credits of 1.5, and allocations of 33.33% all work inside the weighted average formula, because the total of weights normalizes any scale.

No, weights do not have to add up to 100%. Credits of 4, 3, and 5 total 12 and still produce a correct weighted average, since the division by the sum of weights rescales the weighted sum automatically.

Yes, a weighted average handles negative numbers. Negative values, such as a −4.2% return, calculate normally. Negative weights push the result outside the range of the values, so the calculator flags any negative weight in the entry area.

Calculate a weighted average in Excel with =SUMPRODUCT(A2:A10,B2:B10)/SUM(B2:B10), where column A holds the values and column B holds the weights. SUMPRODUCT builds the weighted sum, and SUM builds the total of weights.

Calculate a weighted average in Google Sheets with =AVERAGE.WEIGHTED(A2:A10,B2:B10), where A2:A10 holds the values and B2:B10 holds the weights. The SUMPRODUCT formula from Excel works in Google Sheets too.

Calculate a weighted average for grades by multiplying each grade value by its grade weight, adding those weighted grade values, then dividing by the total weights. Scores of 92, 78, and 85 at weights of 20%, 30%, and 50% produce a final grade of 84.30.

Multiply the coursework mark by 40, multiply the exam mark by 60, add both weighted grade values, then divide by 100. Coursework of 72 and an exam of 65 produce a course grade of 67.80.

Weighted GPA counts course difficulty and unweighted GPA ignores it. Unweighted GPA caps at 4.0 on the 4-point grading scale, while weighted GPA adds 1.0 for AP courses and IB courses and 0.5 for Honors courses, which lifts a high school GPA above 4.0.

Calculate a weighted average interest rate by weighting each rate by its loan balance. Balances of $20,000 at 6% and $5,000 at 3% produce (120,000 + 15,000) ÷ 25,000, a weighted average interest rate of 5.4%.

Yes, you can average averages, on the condition that each average carries the count behind it as its weight. Averaging averages without weights treats a group of 900 students and a group of 30 students as equals.

No, the average of averages is not accurate at unequal group sizes. Class averages of 90 across 10 students and 60 across 90 students return 75 unweighted, while the weighted average returns 63 — a 12-point error.