Average values that carry different weights — and find the grade you need on the next test.
A weighted average is what you use when the values do not count the same. A final exam worth 50% of the grade should not be averaged with a quiz worth 10% as if they were equals: each value is multiplied by its weight, the products are added, and the total is divided by the sum of the weights. When every weight is identical, the weighted average collapses into the ordinary average — which is why the tool shows both, side by side, so you can see how much the weights are actually changing the outcome.
The second mode reverses the question. Instead of asking what your average is, it asks what you still need. Give it the average you are aiming for and the weight of the next assessment, and it solves the same equation for the missing value: the target multiplied by the total weight, minus the points you already earned, divided by the weight of the assessment still to come. If the answer comes out above the maximum grade your school gives, the target is no longer reachable with that single assessment; if it comes out at zero or below, you have already secured it.
Weights do not have to add up to 100 or to 10 — they can be percentages, credit hours, quantities or any numbers at all, because the division by their sum normalises everything. That makes the same calculator work for school grades, for university GPAs weighted by credits, for a weighted average price across purchases of different sizes, and for scoring models where each criterion has its own importance. Decimal commas are accepted, and every calculation happens in your browser.
Weighted average = Σ(value × weight) ÷ Σ(weight) · Grade needed = ( target × (Σweight + weight of the next assessment) − Σ(value × weight) ) ÷ weight of the next assessment.
A simple average treats every value as equally important; a weighted average multiplies each value by its weight first. They only give the same result when all the weights are equal.
No. Weights of 2, 3 and 5 work exactly like 20%, 30% and 50%, because the formula divides by the sum of the weights. Use whatever numbers your school or your problem uses.
Then that target cannot be reached with this assessment alone — you would need a grade the scale does not allow. Lower the target or check whether other assessments are still pending.
Yes. Both comma and dot are accepted as decimal separators, so 8,5 and 8.5 mean the same thing.
No. Everything is calculated locally in your browser and nothing is transmitted or stored.
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