Gravity Forms Telephone Validation (UK Number with Maximum and Minimum Digits)

/Gravity Forms Telephone Validation (UK Number with Maximum and Minimum Digits)

Recently a client needed a function or two for Gravity Forms to process UK telephone numbers, and asked that they are between 7 and 15 characters in length. The following Gravity forms filters do exactly what’s needed.

Paste them in to your theme’s function.php and with a little modification you should be good to go.

UK Phone Number Format

Using a simple regex function, we can create a new mask for telephone fields that eliminates unnecessary characters for validation and return the default error if it’s incorrect, like so:

add_filter( 'gform_phone_formats', 'uk_phone_format' );
function uk_phone_format( $phone_formats ) {
    $phone_formats['uk'] = array(
        'label'       => 'UK Telephone Number',
        'mask'        => false,
        'regex'       => '/^(((\+44\s?\d{4}|\(?0\d{4}\)?)\s?\d{3}\s?\d{3})|((\+44\s?\d{3}|\(?0\d{3}\)?)\s?\d{3}\s?\d{4})|((\+44\s?\d{2}|\(?0\d{2}\)?)\s?\d{4}\s?\d{4}))(\s?\#(\d{4}|\d{3}))?$/',
        'instruction' => false,
    return $phone_formats;

That function adds an additional option (UK Telephone Number) to the Phone Format box when editing the Gravity Form field as shown below.

Limit Between a Certain Number of digits

Not the most elegant of functions, but working well all the same, the function below sets a minimum and maximum number of characters for a Gravity Form field, and displays a different error message for each. The part of the function that says ‘gform_field_validation_1_5‘ indicates the location/ID of the field (Form 1, Input Field 5).

// Add Gravity Forms Min and Max Character Length

add_filter("gform_field_validation_1_5", "validate_chars_count", 10, 4);
    function validate_chars_count($result, $value, $form, $field){

if (strlen($value) < 7) { // Minimum number of allowed characters 
$result["is_valid"] = false; 
$result["message"] = "Please enter at least 7 numbers.";

if (strlen($value) > 15 ) { // Maximum number of allowed characters
    $result["is_valid"] = false;
    $result["message"] = "Please enter less than 15 numbers.";
return $result;

2018-06-22T16:05:33+00:00June 22nd, 2018|Web Programming, WordPress Snippets|0 Comments

About the Author:

Warren Chandler is a freelance web programmer and web developer, based in Frinton on Sea, Essex. Warren specialises in web programming, web design, corporate identity, copy writing, SEO, logo and print media for home, work, and mobile platforms.

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