Limited support A good fit for analytics, totals, and scientific calculations where accumulated rounding error matters.

Math.sumPrecise()

The Math.sumPrecise() static method takes an iterable of numbers and returns the sum of them. It is more precise than summing them up in a loop, because it avoids floating point precision loss in intermediate results.

MathPrecisionNumbers

Browser support

Feature Desktop Mobile
Chrome
Edge
Firefox
Safari
Chrome Android
Safari iOS
javascript.builtins.Math.sumPrecise
147
147
137
26.2
147
26.2
1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)

Syntax

JAVASCRIPT 
// Standard addition results in rounding errors
0.1 + 0.2 + 0.3; // 0.6000000000000001

// Precise sum
Math.sumPrecise([0.1, 0.2, 0.3]); // 0.6

Live demo

Compare normal addition and sumPrecise

Check whether Math.sumPrecise improves floating-point summation in the current runtime.

JavaScript
Output
Press the Run button

Sum many fractional values

Test repeated decimal values where floating-point error tends to accumulate.

JavaScript
Output
Press the Run button

Use a fallback helper

Build a small helper that prefers Math.sumPrecise when present.

JavaScript
Output
Press the Run button

Use cases

  • Financial-style totals

    Reduce rounding drift when summing many decimal values for reporting or reconciliation.

  • Numeric aggregation

    Use more stable summation in charting, measurement, or simulation results.

Cautions

  • Improved summation helps, but it does not remove every precision concern in floating-point workflows.
  • Keep the numeric model explicit if the domain requires exact decimal semantics.

Accessibility

  • More accurate totals support trustworthy user-facing summaries and announcements.
  • If numbers drive status messages or billing UI, precision improvements can reduce confusing discrepancies.

Related links