Math.round()

Math.round() 함수는 입력값을 반올림한 수와 가장 가까운 정수 값을 반환합니다.

문법

Math.round(x)

매개 변수

x

반환 값

입력값을 반올림한 값과 가장 가까운 정수를 의미합니다.

Description

If the fractional portion of the argument is greater than 0.5, the argument is rounded to the integer with the next higher absolute value. If it is less than 0.5, the argument is rounded to the integer with the lower absolute value.  If the fractional portion is exactly 0.5, the argument is rounded to the next integer in the direction of +∞.  Note that this differs from many languages' round() functions, which often round this case to the next integer away from zero, instead giving a different result in the case of negative numbers with a fractional part of exactly 0.5.

Because round() is a static method of Math, you always use it as Math.round(), rather than as a method of a Math object you created (Math has no constructor).

Examples

Math.round( 20.49); //  20
Math.round( 20.5 ); //  21
Math.round( 42   ); //  42
Math.round(-20.5 ); // -20
Math.round(-20.51); // -21

Specifications

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262)
The definition of 'Math.round' in that specification.
Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.round' in that specification.
Standard  
ECMAScript (ECMA-262)
The definition of 'Math.round' in that specification.
Living Standard  

Browser compatibility

BCD tables only load in the browser

See also