Programmatically Update ACF Fields

Use update_field() and update_sub_field() to set ACF field values from code, with the correct value formats for each field type.

php hooks
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Use update_field() and update_sub_field() to set ACF field values from code, with the correct value formats for each field type.

Basic field types — pass the value directly:

<?php
$post_id = 123;

// Text, textarea, number, email, URL.
update_field( 'company_name', 'Acme Corp', $post_id );

// True/false.
update_field( 'is_featured', true, $post_id );

// Date picker (Ymd format).
update_field( 'event_date', '20260415', $post_id );

// Select (single value).
update_field( 'status', 'active', $post_id );

// Select (multiple values) or checkbox.
update_field( 'categories', [ 'design', 'development' ], $post_id );

Image, file, and post object fields — pass the ID:

<?php
// Image or file field — pass attachment ID.
update_field( 'hero_image', 456, $post_id );

// Post object (single) — pass post ID.
update_field( 'related_page', 789, $post_id );

// Relationship — pass array of post IDs.
update_field( 'related_articles', [ 10, 20, 30 ], $post_id );

// Taxonomy — pass array of term IDs.
update_field( 'product_categories', [ 5, 12 ], $post_id );

Add a row to a repeater field:

<?php
add_row( 'team_members', [
    'name'  => 'Jane Smith',
    'role'  => 'Developer',
    'email' => 'jane@example.com',
], $post_id );

Update a specific repeater row (1-indexed):

<?php
// Update row 2's 'role' sub-field.
update_sub_field( [ 'team_members', 2, 'role' ], 'Senior Developer', $post_id );

Update an options page field:

<?php
update_field( 'company_phone', '03 9000 0000', 'option' );

Update a taxonomy term field:

<?php
update_field( 'brand_color', '#FF6600', 'term_42' );

Related Snippets

php hooks

Add Custom Validation to an ACF Field

Use the acf/validate_value filter to add custom server-side validation with error messages.

add_filter( 'acf/validate_value/name=description', function ( $valid, $value, $field, $input_name ) {
    if ( $valid !== true ) {
        return $valid;
    }
php hooks

Auto-Generate Post Title from ACF Fields

Automatically set the post title and slug from ACF field values on save, removing the need for editors to type a title.

add_action( 'acf/save_post', function ( $post_id ) {
    if ( get_post_type( $post_id ) !== 'staff' ) {
        return;
    }
php hooks

Dynamically Populate an ACF Select Field's Choices

Use the acf/load_field filter to populate a select, checkbox, or radio field with dynamic options.

add_filter( 'acf/load_field/name=related_service', function ( $field ) {
    $field['choices'] = [];

    $posts = get_posts( [
php hooks

Get All Fields from a Field Group Programmatically

Use acf_get_fields() to retrieve all field definitions from a specific field group for dynamic forms, exports, or documentation.

$fields = acf_get_fields( 'group_event_details' );

if ( $fields ) {
    foreach ( $fields as $field ) {

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