Grade Curve Calculator illustration

Grade Curve Calculator

Paste raw scores (or a Name, score gradebook CSV) and pick a curving method: add flat points, add points so the best becomes 100, multiply so the best becomes 100, square-root curve, shift to a target mean, or fit a bell curve. Compare every method on the same scores, map results to letter grades with editable cutoffs, download CSV, or print a teacher summary with the histogram.

Numbers separated by commas/spaces, or one "Name, score" per line (CSV paste).
Used for pass-rate before/after (and in Compare).
Minimum score for each letter, e.g. A:90, B:80.

Notes

  • “Add points so best = 100” gives everyone the same bump (gaps stay the same size). “Multiply so best = 100” stretches every score by the same factor (gaps grow).
  • The square-root curve helps low scores most (25 → 50) and leaves 100 unchanged — a common choice after an unexpectedly hard exam.
  • Bell curving forces the class to a chosen mean and spread; it can lower top scores unless you cap the curve, and it makes grades relative rather than absolute.
  • Paste a gradebook as Name, score lines (optional header). Use Download CSV on the results table, or Print summary for a handout with the histogram.

Explore the idea

This interactive demo needs JavaScript.