JavaScript (ES2026) reference · Number Methods and Properties

JavaScript number.toPrecision() Method

Format a number to a given number of significant digits, using exponential notation when needed.

JavaScript (ES2026) Since ES3

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Syntax

number.toPrecision(precision)

Parameter	Description
`precision` optional	Significant digits, 1 to 100.

A string.

Significant digitsTry it yourself

const n = 123.456;
console.log(n.toPrecision(4), n.toPrecision(2), (0.000123).toPrecision(2));

Output

123.5 1.2e+2 0.00012

Large numbers switch to exponential notationTry it yourself

console.log((1234567).toPrecision(3));

Output

1.23e+6

Version	Change
JavaScript ES3	Added

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