I'm trying to display the file size of a file uploaded in Assets. I can get it to display the number of bytes in the file. https://craftcms.com/docs/templating/craft.assets#size

Is there a way to format that number to Mb's?

3 Answers 3


This should do it:

{% set bytes = asset.size %}
{% set kiloBytes = (bytes / 1024)|round(2) %}
{% set megaBytes = (kiloBytes / 1024)|round(2) %}

bytes = {{ bytes }}
kiloBytes = {{ kiloBytes }}
megaBytes = {{ megaBytes }}

You can look at Twig's number_format filter if you want to get fancy with how to display the numbers.


You now can use the filesize filter: https://docs.craftcms.com/v3/dev/filters.html#filesize. This will make the file size readable, and the unit will be selected automatically.

  • 1
    As an extension to this answer, as it is specific to the question, as of Craft 3.1.21 the filesize filter now formats using metric units: github.com/craftcms/cms/blob/develop/…
    – Jamie Wade
    Commented Apr 10, 2019 at 16:20
  • 4
    I've discovered that you can even round the |filesize filter by adding a round parameter: |filesize(1). Maybe there's even more?
    – outline4
    Commented Oct 15, 2019 at 7:47

As mentioned before, the filesize filter is your friend: https://craftcms.com/docs/4.x/dev/filters.html#filesize

Internally, this uses a yii Formatter. You can supply additional arguments to the filter. Here is a link to the function Craft is calling internally: https://www.yiiframework.com/doc/api/2.0/yii-i18n-formatter#asShortSize()-detail

Be aware that Craft's default base for calculating file sizes is 1000, not 1024. This leads to some unwanted results while I was working with it. I ended up overriding the global setting like this:

Craft::$app->formatter->sizeFormatBase = 1024;

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