No, WhatsApp calls will not ring if the person you are calling has their phone turned off [1]. When the recipient's phone is off or not connected to the internet, the call will not go through and will not ring on their end.

WhatsApp operates using an internet connection, either through mobile data or Wi-Fi. WhatsApp calls are made through Voice over Internet Protocol (VoIP) technology, which converts your voice into a digital signal and transmits it over the internet. Therefore, if the recipient's phone is off or not connected to the internet, the call cannot be received [3].

However, WhatsApp does offer voicemail functionality, allowing callers to leave messages when you are unable to answer. This means that even if the person's phone is off, they will receive a notification of a missed call when they turn their phone back on [3].

Learn more:

1. Can WhatsApp ring even if the person you are calling ... - Quora
2. Phone Switched Off But WhatsApp Working? - Techzillo
3. Will Whatsapp Ring if Phone is Off?