Weighted Percentile & Rank Calculator

Find the percentile rank for weighted datasets such as graded assignments, sales buckets, or NPS responses. Provide the cumulative weight below the score, the weight at the score, and the total weight to receive the interpolated percentile.

Sum of all weights in the distribution.
Cumulative weight strictly less than the score of interest.
Weight assigned to observations equal to the target score.
Optional. Defaults to 0.50 to use the midpoint convention.

Examples

  • Total weight 1,200, below 780, weight at score 90, midpoint interpolation ⇒ percentile 68.75%
  • Total weight 5,000, below 3,600, weight at score 800, interpolation 0.30 ⇒ percentile 76.80%

FAQ

How do I obtain the cumulative weights?

Sort the distribution by score, then sum weights strictly less than the target score; the sum at the score becomes the weight at value.

Can I reverse the calculation to find the score at a percentile?

Yes. Rearranging the same formula allows you to solve for the required cumulative weight cut-off when targeting a specific percentile.

What if weights do not sum to one?

No problem—the formula normalises by total weight automatically, so percentages remain valid for any positive total.

Additional Information

  • The calculation mirrors weighted percentile rank = (weight below + fraction × weight at) ÷ total weight.
  • Interpolation fraction lets you select minimum (0), midpoint (0.5), or maximum (1) conventions to match reporting standards.
  • Use consistent units for weights—students, units sold, or response weights all work as long as totals align.

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