How to find out the exact number of followers on YouTube?

According to the official YouTube Data API docs, the only way to obtain the subscriber count of a given channel is through the following properties:

statistics.subscriberCount (unsigned long)
The number of subscribers that the channel has. This value is rounded down to three significant figures. Please see the Revision History or the YouTube Help Center for more details about how subscriber counts are rounded.

statistics.hiddenSubscriberCount (boolean)
Indicates whether the channel's subscriber count is publicly visible.

The number provided is rounded -- thus is not exact. Consequently, however unfortunate, is true that you cannot obtain the info you're looking for from the YouTube Data API.


According to this support post (the emphasis below is mine):

To create more consistency everywhere that we publicly display subscriber counts, starting in August 2019, we’ll begin showing the abbreviated subscriber number across all public YouTube surfaces. Third parties that use YouTube’s API Services will also access the same public facing counts you see on YouTube. Creators will still be able to see their exact number of subscribers in YouTube Studio.

The change will take place across YouTube and the public YouTube Data API Service. Creators will continue to see their full subscriber counts privately in YouTube Studio and YouTube Analytics.

Indeed exact numbers are shown only to creators within YouTube Studio or YouTube Analytics only.