JavaScript

Oct 17, 2026 · Fundamentals

Stop Using reduce for Sums: JavaScript's Math.sumPrecise() Explained

This article explains how JavaScript's reduce method loses precision when summing large or many numbers due to floating-point rounding, introduces the new ES2026 Math.sumPrecise() method that avoids intermediate rounding errors, demonstrates its accuracy with examples like summing 1e20, 0.1, -1e20 and 1000 times 0.1, and notes current browser support.