Fix jQuery formula

I am blocked in a simple jquery calculation and I don't know what to do.

jQuery(document).ready(function(){
    var totalCost = null;
    var periodNotice = 'Select subscription period';
 jQuery("#credits").change(function(){
 var selectedCredit = jQuery(this).val();
 var crm = jQuery(this).children("option:selected").text();
 jQuery("#crm").val(crm);
 jQuery("#mcost").val(selectedCredit);

jQuery(".calc").click(function(event) {
    var total = 0;
    jQuery(".calc:checked").each(function() {
                    var period = jQuery('.period:checked').val();
                    var mailwizz = jQuery('.mailwizz:checked').val();
        total = parseInt(jQuery(mcost).val()) * parseInt(jQuery(period).val()) + parseInt(jQuery(mailwizz).val());

    });
    
    if (total == 0) {
        jQuery('#tcost').val('');
    } else {                
        jQuery('#tcost').val(total);
    }
});
});
});

myform

The formula is MONTHLY COST * SUBSCRIPTION PERIOD (1 OR 12) + MAILWIZZ CHECKBOX (0 or 88)

Thank you in advance!