Convert to boolean: bool

The bool template function converts a value to a boolean (true or false). It recognizes common truthy values like true, yes, on, enable, and 1, as well as falsy values like false, no, off, disable, and 0. If the value cannot be recognized as either, bool raises an error. If you provide a default, it returns the default instead.

This is useful when working with entityAn 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] states or attributes that represent on/off or yes/no values as strings. For example, some sensorsSensors return information about a thing, for instance the level of water in a tank. [Learn more] report on or off as their state, and you might need to convert that to a proper boolean for use in a condition or calculation. The bool function understands all the common representations of true and false that appear throughout Home Assistant.

Usage

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

{{ bool("yes") }}

true

{{ "off" | bool }}

false

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 = are usually required. A few optional parameters have no default value, so the signature shows them without a = as well. To check whether a parameter is required, look at the parameter list below the signature. Each parameter is marked as Required or Optional.

The most common optional parameter without a default value is default. The default parameter sets the value a function returns when the function can’t produce a result, for example, when float gets text that isn’t a number. If you leave out default, there is no fallback value, so most functions raise an error and the template fails. The parameter list of each function says what happens. If you set default, the function returns your value instead.

round(
    value: Any,
    precision: int = 0,
    method: str = "common",
    default: Any,
) -> float | int | Any

bool(
    value: Any,
    default: Any,
) -> bool | Any

Function parameters

The following parameters can be provided to this function.

Recognized values

The function and the filter convert the following values to true: true, yes, on, enable, 1.

It converts the following values to false: false, no, off, disable, 0.

All text comparisons are case-insensitive, so True, TRUE, and true all work. Spaces at the start or end of the text are ignored.

Using a default value

If the input might be an unexpected value, provide a default to prevent errors.

{{ bool("maybe", default=false) }}

false

Good to know

• Only specific words are recognized as boolean. "unavailable" or "unknown" are not, so pass a default when reading sensor states.
• Comparisons are case-insensitive, so "YES", "Yes", and "yes" all convert to true.
• Any number other than 0 converts to true, including decimals like 0.5. The number 0 converts to false.
• The booleans true and false are returned unchanged.
• Other values, such as none, raise an error unless you pass a default.

Try it yourself

Ready to test this? Open Settings > 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.

Convert a state for use in a condition

Check whether a switch-like sensor reports a truthy value.

{% if states("sensor.night_mode") | bool(false) %}
  Night mode is active
{% else %}
  Normal mode
{% endif %}

Night mode is active

Use with iif for display text

Combine bool with iif to convert a state into a human-readable label.

{{
  states("input_boolean.guest_mode") | bool(false)
  | iif("Guests expected", "No guests")
}}

Guests expected

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:

• Immediate if (ternary): iif - Shorthand for basic if/else logic in a single expression.

• Test if value is numeric: is_number - Tests whether a value can be converted to a finite number.

• Convert to integer: int - Converts a value to an integer, with an optional default if conversion fails.

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