Подробные видеоинструкции Wordpress на тему: "Calculated fields form wordpress":
Calculated Fields Form – WordPress plugin
Calculated Fields Form: Plugin Overview and Review
Создание калькулятора и опроса на WordPress: Плагин Calculated Fields Form
How to Add a Custom Calculator in WordPress with Calculated Fields Form
[WP плагин #6] Calculated Fields Form - универсальный калькулятор для Wordpress