SHA1 hash: sha1

The sha1 template function calculates the SHA1 hash of a string and returns the result as a hexadecimal string. SHA1 produces a 160-bit (40-character hex) hash value from any input string.

This is useful when you need a longer hash than MD5 for generating identifiers or checksums. SHA1 provides a 40-character hex output compared to MD5’s 32 characters. Like MD5, it is not recommended for security-sensitive purposes. For cryptographic use cases, prefer sha256 or sha512.

Usage

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

{{ sha1("Hello, World!") }}

0a0a9f2a6772942557ab5355d76af442f8f65e01

{{ "Hello, World!" | sha1 }}

0a0a9f2a6772942557ab5355d76af442f8f65e01

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

sha1(
    value: str,
) -> str

Function parameters

The following parameters can be provided to this function.

Good to know

• SHA1 is no longer considered secure for cryptographic use. Prefer sha256 or sha512 for anything sensitive.
• The result is always a 40-character lowercase hexadecimal string.

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.

Generate a unique identifier

Create a consistent identifier from a combination of entity ID and date.

{{ sha1("sensor.temperature_" ~ now().date() | string) }}

b2e5f8a1c3d4e6f7a8b9c0d1e2f3a4b5c6d7e8f9

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:

• MD5 hash: md5 - Calculates the MD5 hash of a string.

• SHA256 hash: sha256 - Calculates the SHA256 hash of a string.

• SHA512 hash: sha512 - Calculates the SHA512 hash of a string.