You can initiate a call to your contact from WhatsApp Web to your phone instantly with InTouchApp Extension.
Before you proceed, you need InTouchApp installed on your phone & InTouchApp Extension installed on Chrome or Firefox. Learn more.
How to Initiate a Call from WhatsApp Web to phone:
Step 1 - Open web WhatsApp in the browser and Scan the QR code by using WhatsApp.
Step 2 - Go to the contact you want to call and click on the down-arrow as shown in the image below
Step 3 - Choose the option Call contact.
Step 4 - Open your phone's dialer and you will see the contact number automatically placed there. Now go ahead and call the person.