Weighted Average Calculator

A weighted average calculator gives each value a different level of importance before combining them into a single mean. Unlike a simple average — where every number counts equally — a weighted average lets you reflect how much each value actually matters. Enter your values and their matching weights to get the weighted mean instantly.

How to use this calculator

1. Enter your values in the Values box, separated by commas or spaces (for example, 85, 90, 78).
2. Enter the matching weights in the Weights box in the same order as the values. Weights can be decimals (0.40, 0.35, 0.25), whole numbers (40, 35, 25), or credit hours — the calculator normalises them automatically by dividing each product by the total weight.
3. Read the Weighted Average result below the tool.

The number of values and weights must match; the calculator flags a mismatch before it runs.

Worked example

A student has three graded components with these scores and weights:

• Assignment: 85, weight 0.40
• Midterm exam: 90, weight 0.35
• Final exam: 78, weight 0.25

Step 1 — multiply each value by its weight:

85 × 0.40 = 34.00
90 × 0.35 = 31.50
78 × 0.25 = 19.50

Step 2 — sum the products:

34.00 + 31.50 + 19.50 = 85.00

Step 3 — divide by the total weight:

sum of weights = 0.40 + 0.35 + 0.25 = 1.00
weighted average = 85.00 / 1.00 = 85.00

The weighted grade is 85.00. Because the weights already sum to 1, the division changes nothing here — but the formula still handles any set of weights automatically. For a full treatment of weighted means and other measures of location, see the NIST/SEMATECH e-Handbook — Measures of Location.

Frequently asked questions

What is a weighted mean?

The weighted mean is another name for the weighted average. Both terms describe the same calculation: multiply each value by its weight, add the products, and divide by the total weight.

How do I calculate a weighted grade?

Multiply each component score by its weight (as a decimal fraction of the total), sum the results, then divide by the sum of all weights. If weights are given as percentages that add to 100, divide each by 100 first, or keep them as whole numbers — the division at the end normalises them either way.

When should I use a weighted average instead of a regular average?

Use a weighted average any time different values contribute unequally to the outcome — for example, a university GPA where courses carry different credit hours, an investment portfolio where positions are different sizes, or a project score where tasks have different point values.

Does it matter how I express the weights?

No. The formula divides the sum of (value × weight) by the sum of all weights, so the scale cancels out. Weights of 4, 3, 3 give the same result as 0.4, 0.3, 0.3 or 40, 30, 30.