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var fileSize = require("file-size")

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file-size v1.0.0

Lightweight filesize to human-readable / proportions w/o dependencies.



File-size module for node.js for converting, manipulating, and handling file-sizes.


  • Zero Dependencies.
  • Supports IEC (power 1024, default), SI (power 1000), and JEDEC (Alternative SI Unit Notation).
  • Conversion from bytes to K, M, G, and so forth...
  • Customizable human-readable output.


$ npm install file-size

Now require it in your files like so:

var filesize = require('file-size');


filesize(Number bytes, Object options)

Using filesize is very easy, a lot easier if you know the Specification Table. However, it's not required to know it, and in most cases you won't need it.


Filesize works in a jQuery chainable manner so you can use multiple instances without trouble.

var size = filesize(186457865);


var size = filesize(186457865, {
  fixed: 2,
  spacer: ' '
  • fixed - Number of positions after the decimal to show, default is 2
  • spacer - Space between the number and the unit, default is a space

size.human(String spec) -> String

Generates human readable filesize.

  • spec can be one of the following:
    • si
    • iec
    • jedec
IEC Specification


Power of 1024

// outputs: 177.82 MiB
SI Specification

Power of 1000

// outputs: 186.46 MB
JEDEC Specification

Changes IEC default unit notation iB to B for the following: KB, MB, GB

The rest are in iB notation, as per JEDEC Specification.

// outputs: 186.46 MB
filesize(186457865).human('jedec'); unit, String spec) -> String

Converts bytes to another filesize unit

  • unit of size can be one of the following:
    • B, KB, MB, GB, TB, PB, EB, ZB, YB
  • spec can be one of the following:
    • si
    • iec
    • jedec
IEC Specification


// outputs: 177.82
SI Specification
// outputs: 186.46
filesize(186457865).to('MB', true);

size.calculate(String spec) -> Object

Calculates suffix, magnitude, fixed, non-fixed, bits (fixed, non-fixed) from specified bytes against the specified spec.

  • spec can be one of the following:
    • si
    • iec
    • jedec
 * outputs:
 *    {
 *      suffix: 'Bytes',
 *      magnitude: 0,
 *      result: 8,
 *      fixed: '8.00',
 *      bits: { result: 1, fixed: '1.00' }
 *    }

var result = filesize(8).calculate()


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