Hidden Input

A field that stores a value without displaying an editable input to editors. Supports a static default value or dynamic tokens that resolve at save time — useful for recording metadata like which user saved a post, the save date, or the current post ID.

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Pro field

Hidden Input requires the Extra Fields for ACF Pro license.

Settings

SettingDefaultOptionsDescription
Default Value(empty)Any stringStatic value stored when no dynamic token is selected.
Dynamic Token(none)user_id · post_id · date · timeAuto-populates the field with a resolved value at save time.
Auto Updatefalseon/offRe-evaluate and overwrite the token value on every save (not just the first).

Dynamic tokens

TokenResolves to
{{user_id}}Current logged-in user’s ID
{{post_id}}Current post’s ID
{{date}}Current date in Y-m-d format
{{time}}Current time in H:i:s format

Return values

Returns a plain string — the static default or the resolved token value.

$user_id = get_field('created_by');
// "42"

$save_date = get_field('last_modified_date');
// "2026-06-15"

Usage

Recording who created a post

  1. Add a Hidden Input field named created_by.
  2. Set Dynamic Token to {{user_id}}.
  3. Leave Auto Update disabled (so it only captures the original author).
$creator_id = (int) get_field('created_by');
$creator    = get_userdata($creator_id);

if ($creator) {
    echo 'Posted by: ' . esc_html($creator->display_name);
}

Tracking the last save date

  1. Add a Hidden Input named last_saved.
  2. Set Dynamic Token to {{date}}.
  3. Enable Auto Update so it refreshes on every save.
$saved = get_field('last_saved');
if ($saved) {
    echo 'Last updated: ' . esc_html(date_format(date_create($saved), 'F j, Y'));
}

Static version flag

  1. Add a Hidden Input named schema_version.
  2. Set Default Value to 2 (or whatever your current schema version is).
  3. No token needed.
$version = get_field('schema_version');
if ((int)$version < 2) {
    // Run a migration for old posts
}

Querying by saved date

// Get posts saved today
$posts = get_posts([
    'meta_query' => [[
        'key'   => 'last_saved',
        'value' => date('Y-m-d'),
    ]],
]);