Newly available Best for specialized numeric and graphics workflows. Ordinary application code usually does not need half-precision arrays.

Float16Array

The Float16Array typed array represents an array of 16-bit floating point numbers in the platform byte order. If control over byte order is needed, use DataView instead. The contents are initialized to 0 unless initialization data is explicitly provided. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

Float16Array is a subclass of the hidden TypedArray class.

Note: Float16 support is not universal, both in the JavaScript API and the underlying CPU architecture. Using it may result in slower performance on some platforms. It is intended for interacting with highly optimized and performance-sensitive systems such as float-backed canvases, WebGPU, WebGL, and deep learning models including stable diffusion.

Typed arraysNumeric dataPerformance

Browser support

Feature Desktop Mobile
Chrome
Edge
Firefox
Safari
Chrome Android
Safari iOS
Float16Array
135
135
129
18.2
135
18.2
DataView.getFloat16

The getFloat16() method of DataView instances reads 2 bytes starting at the specified byte offset of this DataView and interprets them as a 16-bit floating point number. There is no alignment constraint; multi-byte values may be fetched from any offset within bounds.
135
135
129
18.2
135
18.2
DataView.setFloat16

The setFloat16() method of DataView instances takes a number and stores it as a 16-bit floating point number in the 2 bytes starting at the specified byte offset of this DataView. There is no alignment constraint; multi-byte values may be stored at any offset within bounds.
135
135
129
18.2
135
18.2
Float16Array.Float16Array

The Float16Array() constructor creates Float16Array objects. The contents are initialized to 0 unless initialization data is explicitly provided.
135
135
129
18.2
135
18.2
Math.f16round

The Math.f16round() static method returns the nearest 16-bit half precision float representation of a number.
135
135
129
18.2
135
18.2
1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)

Syntax

JAVASCRIPT 
const f16 = new Float16Array([1.5, 2.5, 3.5]);
console.log(f16); // Float16Array [1.5, 2.5, 3.5]

// Rounding to half precision using Math.f16round
Math.f16round(1.337); // 1.3369140625

Live demo

Check Float16Array support

Create a Float16Array when the constructor exists.

JavaScript
Output
Press the Run button

Inspect byte length

Compare the memory size of Float16Array and Float32Array.

JavaScript
Output
Press the Run button

Map over half-precision values

Transform half-precision values while keeping the typed-array structure.

JavaScript
Output
Press the Run button

Use cases

  • ML-style buffers

    Store model-related numeric data in a more compact format when full float precision is unnecessary.

  • Graphics pipelines

    Prepare data for rendering and GPU-adjacent workflows where compact buffers are valuable.

Cautions

  • Half precision trades accuracy for size, so verify that the reduced precision is acceptable for the domain.
  • Typed array code becomes harder to read quickly; keep buffer ownership and conversion steps explicit.

Accessibility

  • No direct accessibility effect, but efficient numeric processing can support smoother interactive visuals.
  • Do not use precision-saving optimizations if they degrade the clarity of user-facing values.

Related links