CalculationTime

Weighted Average Calculator

Calculate a weighted mean from values and weights for grade categories, credits, survey scores, index components and spreadsheet checks, with contribution lines, total-weight warnings and a printable weighted-average worksheet record.

Live math canvas

Your numbers, formula and explanation together

Weighted Average Calculator: 355 weighted mean with contribution lines, total-weight check and printable worksheet record. Weighted Average Calculator uses the declared inputs to produce a transparent default result. Value 1: 90 score or percent; Weight 1: 20 weight; Value 2: 80 score or percent; Weight 2: 30 weight; primary comparison: 90 and 20.

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Weighted average = Σ(value × weight) ÷ Σ(weight). If weights are percentages that add to 100, this is the same as adding each value × weight percent ÷ 100.
  1. Apply the formulaWeighted average = Σ(value × weight) ÷ Σ(weight). If weights are percentages that add to 100, this is the same as adding each value × weight percent ÷ 100.355 weighted mean with contribution lines, total-weight check and printable worksheet recordWeighted Average Calculator uses the declared inputs to produce a transparent default result. Value 1: 90 score or percent; Weight 1: 20 weight; Value 2: 80 score or percent; Weight 2: 30 weight; primary comparison: 90 and 20.

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Value 1
90 score or percent
Example: homework average.
Weight 1
20 weight
Value 2
80 score or percent
Example: midterm score.
Weight 2
30 weight
Value 3
85 score or percent
Example: final exam score.
Weight 3
50 weight
Value 4
0 optional
Leave weight 4 as 0 if you only need three rows.
Weight 4
0 optional weight

Resulting answer

355 weighted mean with contribution lines, total-weight check and printable worksheet record

Weighted Average Calculator uses the declared inputs to produce a transparent default result. Value 1: 90 score or percent; Weight 1: 20 weight; Value 2: 80 score or percent; Weight 2: 30 weight; primary comparison: 90 and 20.

Answer
355 weighted mean with contribution lines, total-weight check and printable worksheet record
Live support
Weighted Average Calculator uses the declared inputs to produce a transparent default result. Value 1: 90 score or percent; Weight 1: 20 weight; Value 2: 80 score or percent; Weight 2: 30 weight; primary comparison: 90 and 20.

Assumptions used

What this answer assumes

Best for grade categories, credit-weighted scores, survey indexes, portfolio scorecards and spreadsheet checks where values, weights, contribution math and notes need to stay printable together.

  • Weights must be zero or positive; rows with zero weight are ignored in the weighted result.
  • Weights can be percentages, credits, units or relative importance as long as the same meaning is used across rows.
  • If percent weights are intended, check that the total weight is 100.
  • The calculator computes a weighted mean only; it does not apply school-specific gradebook rules.
  • Missing work should be entered according to the course policy, often as zero if it counts.

Master’s Tip

How to use the result well

Master’s Tip: write down whether weights are category percentages, credits or arbitrary units. The arithmetic is the same, but the meaning of the result depends on the meaning of the weights.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Value 1
90 score or percent
Example: homework average.
Weight 1
20 weight
Value 2
80 score or percent
Example: midterm score.
Weight 2
30 weight

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Formula

Weighted average = Σ(value × weight) ÷ Σ(weight). If weights are percentages that add to 100, this is the same as adding each value × weight percent ÷ 100.

Worked example

Homework is 90 worth 20, midterm is 80 worth 30 and final is 85 worth 50. Weighted average = (90×20 + 80×30 + 85×50) ÷ (20+30+50) = 8,450 ÷ 100 = 84.5.

Professional note

Master’s Tip: write down whether weights are category percentages, credits or arbitrary units. The arithmetic is the same, but the meaning of the result depends on the meaning of the weights.

Regional and unit assumptions

Defaults use a grade-style percent example with weights totaling 100. The formula is general and can also be used for credits, units, frequencies or importance weights.

Assumptions and limitations

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

Weighted average = Σ(value × weight) ÷ Σ(weight). If weights are percentages that add to 100, this is the same as adding each value × weight percent ÷ 100.

Standard or basis

Defaults use a grade-style percent example with weights totaling 100. The formula is general and can also be used for credits, units, frequencies or importance weights.

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Master’s Tip: write down whether weights are category percentages, credits or arbitrary units. The arithmetic is the same, but the meaning of the result depends on the meaning of the weights.

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These cards are resolved from calculator data, category context and live-route status so the page links to useful next steps without hand-built link clutter.

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Questions

What is a weighted average?

It is an average where some values count more than others. Each value is multiplied by a weight before the total is divided by the sum of weights.

Do weights have to add to 100?

Only if you are using percentage weights. Arbitrary weights such as credits or units are normalized by dividing by the total weight.

Is a weighted average the same as GPA?

GPA can use weighted-average ideas, but official GPA rules depend on grade points, credits, repeats and institution policy.

How do I include a missing assignment?

Follow the course policy. If the missing assignment counts as zero, enter 0 as the value with its normal weight.

What if one weight is zero?

A zero-weight row contributes nothing to the result and is ignored except in the printed input list.

Calculation note

Weighted averages are used whenever some observations should count more than others. In school settings, this often appears as categories, credits or exam weights.

Simple average versus weighted average

A simple average gives every value the same importance. A weighted average changes that by letting one value count more heavily, such as a final exam being worth more than a small homework task.

Percent weights and category weights

Gradebooks often use category percentages that add to 100. In that case, each category contribution is its score multiplied by its percent weight.

Arbitrary weights and credits

Weights do not always have to be percentages. Credits, units, frequencies and importance scores can all be used if the final division by total weight is included.

Common mistake

A common error is adding value × weight products but forgetting to divide by total weight when the weights do not add to 100.

Connection to final grades

Final grade calculators are a special weighted-average problem: the current course grade and final exam score each receive a weight in the overall grade.

Sources and further readingWikipedia: Weighted arithmetic meanNIST/SEMATECH e-Handbook: Weighted meanNational Center for Education Statistics