Immediate if (ternary): iif

The iif template function is a shorthand for if/else logic. Give it a condition and two values, and it returns the first when true, the second when false. Think of it as asking a yes/no question: “Is this true? If yes, give me this. If no, give me that.”

In many places throughout Home Assistant, you’ll want to change what is displayed or sent based on the current stateThe state holds the information of interest of an entity, for example, if a light is on or off. Each entity has exactly one state and the state only holds one value at a time. However, entities can store attributes related to that state such as brightness, color, or a unit of measurement. [Learn more] of something. Maybe you want a notificationYou can use notifications to send messages, pictures, and more, to devices. [Learn more] to say “The garage is open” or “The garage is closed” depending on the actual state. Or you want to set a light brightness to 100 when you’re home and 30 when you’re away. Or show “Armed” or “Disarmed” on your dashboard. All of these are choices between two values based on a condition, and iif is designed exactly for that.

Usage

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

{{ iif(states("sensor.temperature") | float > 25, "warm", "cool") }}

warm

{{ is_state("binary_sensor.front_door", "on") | iif("open", "closed") }}

open

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

iif(
    condition: Any,
    if_true: Any = True,
    if_false: Any = False,
    if_none: Any = None,
) -> Any

Function parameters

The following parameters can be provided to this function.

Compared to an if block

iif replaces a multi-line {% if %} block with a single expression. These two templatesA template is an automation definition that can include variables for the action or data from the trigger values. This allows automations to generate dynamic actions. [Learn more] produce the same result:

{% if is_state("binary_sensor.front_door", "on") %}
  open
{% else %}
  closed
{% endif %}

open

{{ is_state("binary_sensor.front_door", "on") | iif("open", "closed") }}

open

Use iif when you need to choose between two values. For more complex logic with multiple branches, use {% if %} / {% elif %} / {% else %} instead.

Good to know

• All arguments are evaluated, even the branch that is not returned. Use an if/else block when one branch could raise an error.
• None is only handled separately when you pass if_none. Otherwise it is treated as falsy.
• Values like 0, empty strings, and empty lists are falsy, so they return if_false, not if_none.

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].

Caveats

All arguments are always evaluated

Unlike an {% if %} block, iif evaluates all its arguments before deciding which one to return. This means both the if_true and if_false values are computed regardless of the condition.

In practice, this is rarely a problem since most arguments are plain strings or numbers. But be aware of it if your arguments contain expressions that could fail:

{{
  has_value("sensor.temperature")
  | iif(
      states("sensor.temperature") | float,
      "unavailable"
    )
}}

In this case, use an {% if %} block instead:

{% if has_value("sensor.temperature") %}
  {{ states("sensor.temperature") | float }}
{% else %}
  unavailable
{% endif %}

None vs other falsy values

Values like 0, empty strings, and false are all falsy. They return the if_false value, not the if_none value. Only a literal None triggers the if_none parameter. If you need to distinguish between 0 and None, you must use the if_none parameter.

More examples

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

Dynamic notification message

Send a notification that adapts its message based on the state of the garage door.

action:
  - action: notify.mobile
    data:
      message: >
        The garage door is
        {{ is_state("cover.garage", "open") | iif("open", "closed") }}.
        {{
          is_state("cover.garage", "open")
          | iif("You might want to close it.", "")
        }}

Handling None values

By default, None is treated as falsy and returns the if_false value. Use the third argument to handle None separately. This is useful when a sensor attribute might not exist.

{{
  state_attr("sensor.weather", "temperature")
  | iif("has temp", "no temp", "sensor unavailable")
}}

This returns:

• has temp when the attribute has a truthy value (like 21.5)
• no temp when the attribute is a falsy value (like 0)
• sensor unavailable when the attribute is None (does not exist)

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:

• Test entity state: is_state - Tests if an entity is in a specific state.

• Get entity state: states - Returns the state value of an entity, or lets you iterate over all entity states.