# At-time test

Learn how to check if a date time is at a specific time of day.

This test checks whether a date or instant is at a specific time of day.

When comparing dates, this test first converts the value to an instant based on the time zone set at the [application level](/explanation/application/overview). It then checks whether the instant is at the specified time of day.

For more information about how dates are converted to instants, see the section on [Date-time conversion](/reference/cql/conversions#date-time).

## Syntax

This test has the following syntax:

```cql
/*<value>*/ is at /*<time>*/
```

To negate the test, you can write:

```cql
/*<value>*/ is not at /*<time>*/
```

## Parameters

These are the supported parameters:

- `value`: `Date | DateTime`

  The date time to match against the specified time of day.

- `time`: `Time`

  The time of day. This can be a time value or a valid ISO 8601 [time string](https://en.wikipedia.org/wiki/ISO_8601#times), such as `12:00:00` or `12:00`.

## Examples

Here is a basic example of how to check whether it is noon:

```cql
now is at "12:00" // false
```

Because the [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601#times) standard allows you to omit subcomponents of a time value, you can also write the previous example as:

```cql
now is at 12 // false
```