There are 3 different methods that you can transfer your WhatsApp contact from an iPhone or an Android phone.
Try "Export Contacts for WhatsApp", it helps a user to fetch those contacts which are using WhatsApp.
Its User Interface is so easy that anyone can use it! A user just has to follow a few simple steps and he is good to go! You can also use this application in Desktop.
If you are a running a business, but not reaching to the right audience then you must try this application. As it can help you to get the consumers which are using the internet! So that you can share them complete information about your business!
You can simply download it from Google Play Store! Hope it will help you!
Thanks and Regards,
Prashant Gandhi