Format byte size as human-readable: filesizeformat

The filesizeformat filter converts a number of bytes into a human-readable file size string, such as 13.2 kB or 4.1 MB. It automatically chooses the appropriate unit (bytes, kB, MB, GB, and larger). By default, it uses decimal (SI) units (1 kB = 1000 bytes), but you can switch to binary units (1 KiB = 1024 bytes) with the binary parameter. This is useful when displaying storage-related information from sensorsSensors return information about a thing, for instance the level of water in a tank. [Learn more], such as disk usage, download sizes, or memory consumption. For example, a sensorSensors return information about a thing, for instance the level of water in a tank. [Learn more] might report a value in bytes, and you can use this filter to display it in a more readable format on a dashboard card or in a notification.

Usage

Here’s how to use this template function. Copy any example and adjust it to your setup.

{{ 1234567890 | filesizeformat }}

1.2 GB

Function signature

The signature is a technical summary of this template function. It shows the name of the function, the values (called parameters) it accepts, and what type of data each parameter expects (for example, a piece of text or a number).

Function parameters that have a = with a value after them are optional. If you leave them out, the default value shown is used automatically. Function parameters without a default are required.

filesizeformat(
    value: int | float,
    binary: bool = False,
) -> str

Function parameters

The following parameters can be provided to this function.

Using binary units

Set binary to true to use binary (IEC) units instead of decimal (SI) units.

{{ 1048576 | filesizeformat(binary=true) }}

1.0 MiB

Good to know

• The default is decimal units (1 kB = 1000 bytes), not binary. Pass binary=true for KiB/MiB/GiB.
• The input must be a number of bytes. Convert state strings with int or float first.

Try it yourself

Ready to test this? Open Developer tools > Template, paste the example into the Template editor, and watch the result update on the right. Edit the values to see how the function adapts to your own entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this function comes up in automations and templates. Copy any example and adapt it to your setup.

Display disk usage from a sensor

Format a disk usage sensor value that reports bytes into a readable size.

{{ states("sensor.disk_used") | int | filesizeformat }}

42.3 GB

Show download size in a notification

Format a file size for display in a notification message.

{{
  "Update available: "
  ~ (states("sensor.update_size") | int | filesizeformat)
}}

Update available: 156.2 MB

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with your template and expected result, or share on our subreddit /r/homeassistant.

Related template functions

These functions work well alongside this one:

• Convert to float: float - Converts a value to a floating-point number, with an optional default if conversion fails.

• Round a number: round - Rounds a numeric value to a specified number of decimal places using various rounding methods.