# Math.f16round()

## Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

The `Math.f16round()` static method returns the nearest 16-bit half precision float representation of a number.

## Syntax

js
``````Math.f16round(doubleFloat)
``````

### Return value

The nearest 16-bit half precision float representation of `doubleFloat`.

## Description

`Math.f16round` is the 16-bit counterpart of `Math.fround()`. It is intended to smooth some rough edges when interacting with float16 numbers, such as when reading from a `Float16Array`. Internally, JavaScript continues to treat the number as a 64-bit float, it just performs a "round to even" on the 10th bit of the mantissa, and sets all following mantissa bits to `0`. If the number is outside the range of a 16-bit float, `Infinity` or `-Infinity` is returned.

Because `f16round()` is a static method of `Math`, you always use it as `Math.f16round()`, rather than as a method of a `Math` object you created (`Math` is not a constructor).

## Examples

### Using Math.f16round()

The number 1.5 can be precisely represented in the binary numeral system, and is identical in 16-bit and 64-bit:

js
``````Math.f16round(1.5); // 1.5
Math.f16round(1.5) === 1.5; // true
``````

However, the number 1.337 cannot be precisely represented in the binary numeral system, so it differs in 16-bit and 64-bit:

js
``````Math.f16round(1.337); // 1.3369140625
Math.f16round(1.337) === 1.337; // false
``````

100000 is too big for a 16-bit float, so `Infinity` is returned:

js
``````Math.f16round(100000); // Infinity
``````

## Specifications

Specification
Float16Array
# sec-math.f16round

## Browser compatibility

BCD tables only load in the browser