Modifier: :timestamp

:timestamp means different things depending on the merge tag or the kind of field:

Unix timestamp

On {date_created}, {date_updated}, {payment_date}, {today}.

Product	Gravity Forms
Requires	Gravity Forms 1.9 or later
Works on	{date_created}, {date_updated}, {payment_date}, {today}
In the picker	What to show

Rendered by real Gravity Forms and GravityKit PHP against a test entry.

Merge tag	Output	Without the modifier
`{date_created:timestamp}`	`1768438800`	`January 15, 2026`
`{date_updated:timestamp}`	`1768439400`	`January 15, 2026`
`{payment_date:timestamp}`	`1768439100`	`January 15, 2026`
`{today:timestamp}`	`1768467600`	`January 15, 2026`
`{date_created:timestamp}` Rendered against an entry nine days older, where the result differs.	`1767672000`	`January 15, 2026`
`{date_updated:timestamp}` Rendered against an entry nine days older, where the result differs.	`1767672600`	`January 15, 2026`
`{payment_date:timestamp}` Rendered against an entry nine days older, where the result differs.	`1767672300`	`January 15, 2026`

On Date, Time fields.

Runs the value through strtotime(). Yields -1 when it is not a parseable date.

Seconds since January 1, 1970: easy to sort or compare in JavaScript.

Write

<time data-timestamp="{Birthday:13:timestamp}">{Birthday:13}</time>

Get

<time data-timestamp="294019200">04/27/1979</time>

Rendered by real Gravity Forms and GravityKit PHP against a test entry.

Merge tag	Output	Without the modifier
`{Birthday:13:timestamp}`	`294019200`	`04/27/1979`

On {now}, {yesterday}, {tomorrow}.

Also switches the relative-date tags to UTC rather than site-local time.

Rendered by real Gravity Forms and GravityKit PHP against a test entry.