The gform_currency filter allows you to override the currency configured on the Forms > Settings page, affecting all forms.
Usage
add_filter('gform_currency', 'your_function_name');
Parameters
- $currency (string): The currency code to be filtered.
 
More information
See Gravity Forms Docs: gform_currency
Examples
Force the currency to USD
This example changes the currency to USD (US dollars).
add_filter('gform_currency', 'usd_currency');
function usd_currency($currency) {
    return 'USD';
}
Force the currency to EUR
This example changes the currency to EUR (Euros).
add_filter('gform_currency', 'eur_currency');
function eur_currency($currency) {
    return 'EUR';
}
Force the currency to GBP
This example changes the currency to GBP (British Pounds).
add_filter('gform_currency', 'gbp_currency');
function gbp_currency($currency) {
    return 'GBP';
}
Force the currency to JPY
This example changes the currency to JPY (Japanese Yen).
add_filter('gform_currency', 'jpy_currency');
function jpy_currency($currency) {
    return 'JPY';
}
Force the currency to AUD
This example changes the currency to AUD (Australian Dollars).
add_filter('gform_currency', 'aud_currency');
function aud_currency($currency) {
    return 'AUD';
}