Using Gravity Forms ‘gform_authorizenet_amount_pre_authorize’ PHP filter

The gform_authorizenet_amount_pre_authorize filter allows you to modify the authorization amount before it is sent to


To use this filter, add it to your theme’s functions.php file:

add_filter('gform_authorizenet_amount_pre_authorize', 'your_function_name', 10, 6);


  • $auth_amount (float): The authorization amount. Defaults to the value of $config['amount'].
  • $transaction (object): The transaction object.
  • $form_data (array): An associative array containing the form title, billing address, payment amount, setup fee amount, line items created using the submitted pricing field values, and any discounts from coupons.
  • $config (array): The feed currently being processed.
  • $form (array): The form currently being processed.
  • $entry (array): The entry currently being processed. (Available since version 2.1.8).

More information

See Gravity Forms Docs: gform_authorizenet_amount_pre_authorize


Override the authorization amount for a specific form

This example shows how to override the authorization amount for a specific form with ID 10:

add_filter('gform_authorizenet_amount_pre_authorize', 'change_amount', 10, 6);

function change_amount($auth_amount, $transaction, $form_data, $config, $form, $entry) {
    if ($form['id'] == 10) {
        $auth_amount = 1;
    return $auth_amount;

Apply a discount to the authorization amount

This example shows how to apply a 10% discount to the authorization amount for a specific form with ID 20:

add_filter('gform_authorizenet_amount_pre_authorize', 'apply_discount', 10, 6);

function apply_discount($auth_amount, $transaction, $form_data, $config, $form, $entry) {
    if ($form['id'] == 20) {
        $auth_amount *= 0.9;
    return $auth_amount;

Set a minimum authorization amount

This example sets a minimum authorization amount of $5 for all forms:

add_filter('gform_authorizenet_amount_pre_authorize', 'set_minimum_amount', 10, 6);

function set_minimum_amount($auth_amount, $transaction, $form_data, $config, $form, $entry) {
    if ($auth_amount < 5) {
        $auth_amount = 5;
    return $auth_amount;

Increase the authorization amount based on a custom field

This example increases the authorization amount by the value of a custom field with ID 5:

add_filter('gform_authorizenet_amount_pre_authorize', 'increase_amount_based_on_custom_field', 10, 6);

function increase_amount_based_on_custom_field($auth_amount, $transaction, $form_data, $config, $form, $entry) {
    $custom_field_value = rgar($entry, '5');
    $auth_amount += $custom_field_value;
    return $auth_amount;

Apply a membership discount

This example applies a membership discount of 15% to the authorization amount for members:

add_filter('gform_authorizenet_amount_pre_authorize', 'apply_membership_discount', 10, 6);

function apply_membership_discount($auth_amount, $transaction, $form_data, $config, $form, $entry) {
    // Check if the user is a member (replace this with your own membership check)
    $is_member = check_user_membership();

    if ($is_member) {
        $auth_amount *= 0.85;
    return $auth_amount;

// Replace this function with your own membership check logic
function check_user_membership() {
    // Example: return true if user is a member, false otherwise
    return true;

These examples demonstrate various ways to use the gform_authorizenet_amount_pre_authorize filter to modify the authorization amount before it is sent to Remember to replace `your_function_name` with an appropriate function name and adapt the code to your specific requirements.