Weighted average calculator
Calculate a weighted average from value/weight rows.
The weighted average calculator takes a list of value/weight pairs and computes Σ(value × weight) ÷ Σweight — useful for any weighting scheme where each value counts more or less based on an associated weight, ratio, or credit count.
Sum of weights
100
Weighted sum
8700
Weighted average
87.00
How to use
- Add a row per value, with a positive weight (a ratio, percentage, or credit count — any consistent unit works).
- Weighted average = Σ(value × weight) ÷ Σweight.
Common use scenarios
- Averaging values where some carry more importance than others.
- Computing a weighted average from ratios, percentages, or credit counts.
- Combining multiple sub-scores into one overall weighted figure.
- Verifying a weighted average calculated in a spreadsheet.
✓Content & verification reviewed: 2026-08-25
How we verify Weighted average calculator
How to confirm every row is valid before trusting the result.
Every row needs both a value and a weight greater than 0
Unlike some averaging tools, this one requires a complete, valid value and a positive weight on every single row — there's no partial-credit handling for incomplete rows.
One invalid row fails the whole calculation, not just that row
This is a key difference from the grade average calculator: here, a single row with a missing value, missing weight, or a weight of zero or less causes the entire calculation to fail rather than being silently skipped — fix or remove the problem row to get a result.
Weight units just need to be internally consistent
You can use any consistent unit for weight — percentages, ratios, credit counts, or something else — as long as every row in the same calculation uses the same kind of unit, since the formula only cares about relative weight, not the specific unit.
Before you rely on the result
- Every row has both a value and a weight filled in.
- Every weight is strictly greater than 0 — zero or negative weights will fail the calculation.
- All weights use the same consistent unit (all percentages, all ratios, etc.).
- If the calculation failed, you've checked for one incomplete or invalid row rather than assuming a broader bug.
Who this is for
- Anyone averaging values where some carry more importance than others.
- People computing a weighted average from ratios, percentages, or credits.
- Anyone combining multiple sub-scores into one overall figure.
- People verifying a weighted average calculated in a spreadsheet.
Real-world examples
Combining weighted sub-scores
Someone combining scores from several evaluation criteria, each with a different importance weight, enters each score/weight pair to get one overall weighted figure.
Portfolio-style weighting
A person averaging returns or ratings across items with different allocation sizes uses the allocation as the weight for each value to get a properly weighted overall average.
Double-checking a spreadsheet formula
Someone who built a SUMPRODUCT-style weighted average formula enters the same value/weight pairs here to confirm the spreadsheet result matches.
Limitations
- Unlike the Grade average calculator, any single invalid row (missing value, missing weight, or weight ≤ 0) fails the whole calculation instead of being skipped.
Frequently asked questions
What happens if I leave a weight blank on one row?
The entire calculation fails with an error — every row needs a complete value and a weight greater than 0, unlike some averaging tools that simply skip incomplete rows.
Can weights be percentages, or do they need to sum to 1?
Weights can be any consistent unit — percentages, ratios, or raw counts — they don't need to sum to any particular total, since the formula divides by the sum of weights automatically.
Why is this different from the grade average calculator?
The grade average calculator skips incomplete rows and still computes an average from the valid ones; this tool requires every row to be complete and valid, or the whole calculation fails.
Can a weight be zero?
No — weights must be strictly greater than 0. A row with a weight of 0 or less will cause the calculation to fail rather than being treated as contributing nothing.
🔒 Runs in your browser — nothing is uploaded. Results are for reference only; see the disclaimer. Last updated: 2026-08-25
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