Home ▸ Template functions

Convert to UNIX timestamp: as_timestamp

The as_timestamp template function converts a datetimeA value representing a specific moment in time, including the date, time, and time zone. For example, 2026-04-05 14:30:00+00:00. Used for timestamps, scheduling, and time-based calculations. object or a date/time string into a UNIX timestamp. The result is a floating-point number representing the number of seconds since January 1, 1970 (the UNIX epoch).

UNIX timestamps are useful when you need to perform arithmetic with dates and times, since they are plain numbers that can be added, subtracted, and compared. For example, you can subtract two timestamps to find the number of seconds between two events, or add a number of seconds to find a future time. Many external services and APIs also expect timestamps in this format. You can convert the result back to a readable date using timestamp_custom, timestamp_local, or as_datetime.

Usage

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

As a function

As a filter

Template

{{ as_timestamp("2024-03-15T14:50:00+01:00") }}

Result (float)

1710510600.0

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.

How to read a signature

Here is the signature of the round filter as an example:

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

round is the name of the function.
Between the parentheses are the parameters. Each parameter has a name, followed by a colon and the type of value the parameter expects. The type only tells you what kind of value to pass. For default: Any, you pass a value of any type, such as 0 or "unknown", not the word Any.
= 0 and = "common" are default values. You can leave out precision and method, and round uses these default values.
default has no =, but the parameter list marks default as optional. If you leave out default and round gets a value that isn’t a number, round raises an error.
-> shows the type of value the function returns.
Inside a signature, | means “or”. This function returns a decimal number, a whole number, or the value you passed as default.

round is a filter, so the first parameter, value, is the value before the |. For example, {{ 3.14159 | round(2) }} returns 3.14.

The types you’ll see most often:

str: text, such as "hello"
int: a whole number, such as 5
float: a decimal number, such as 3.14
bool: true or false
list: a list of values, such as [1, 2, 3]. list[str] is a list of texts.
dict: a set of keys and values, such as {"name": "Kitchen"}
datetime and timedelta: a date and time, and a duration. For details, refer to Dates and times.
None: no value
Any: any type of value

Some signatures use special forms:

*args means you can pass any number of values, separated by commas. For example, average(1, 2, 3).
value | name(...) means the function is a filter. The value before the | is passed to the filter as its first parameter. Some filter signatures, like the round example, show this value as the first parameter between the parentheses instead.

as_timestamp(
    value: datetime | str,
    default: Any,
) -> float | Any

Function parameters

The following parameters can be provided to this function.

value string | datetime Required

The datetime object or date/time string to convert. Strings must be in a recognized date/time format (for example, ISO 8601).

default any (Optional)

The value to return if the conversion fails, such as 0. If you leave out default and the conversion fails, as_timestamp raises an error and the template fails.

Converting the current time

You can convert now or utcnow to get the current UNIX timestamp.

Template

{{ as_timestamp(now()) }}

Result (float)

1710510600.0

Using a default value

If the input might be invalid, provide a default to avoid errors.

Template

{{ as_timestamp("not a date", default=0) }}

Result (float)

Good to know

The result is a UNIX timestamp in seconds (a float), not milliseconds.
Without a default, unparseable strings raise an error.
Subtracting two timestamps gives a duration in seconds, which can be compared directly with numeric thresholds.

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.

Seconds since an entity last changed

Calculate how many seconds have passed since a sensor last changed 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].

Template

{{
  (as_timestamp(now())
   - as_timestamp(states.binary_sensor.front_door.last_changed))
  | int
}}

Result (integer)

Check if something happened in the last 5 minutes

Determine whether the front door opened in the last 300 seconds.

Template

{{
  (as_timestamp(now())
   - as_timestamp(states.binary_sensor.front_door.last_changed))
  < 300
}}

Result (boolean)

true

Format a timestamp for display

Convert a datetime string to a UNIX timestamp and then format it using timestamp_custom.

Template

{{
  as_timestamp("2024-03-15T14:30:00+01:00")
  | timestamp_custom("%H:%M")
}}

Result (string)

14:30

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.

Tip

AI assistants like ChatGPT or Claude can also explain or fix templates when you describe what you want in plain language.

Related template functions

These functions work well alongside this one:

Convert to datetime: as_datetime - Converts a string or timestamp to a datetime object.
Current local date and time: now - Returns the current date and time in your local time zone.
Current UTC date and time: utcnow - Returns the current date and time in UTC.
Format timestamp with custom format: timestamp_custom - Formats a UNIX timestamp as a string using a custom format.
Format timestamp as local time: timestamp_local - Formats a UNIX timestamp as a local datetime string.
Format timestamp as UTC time: timestamp_utc - Formats a UNIX timestamp as a UTC datetime string.

Help us improve our documentation

Was this page helpful?

Suggest an edit to this page, or provide/view feedback for this page.