To find the current estimated number of internet users today, we would typically look at the latest statistics provided by relevant sources such as internet analytics companies, global organizations dealing with information technology, or reputable research institutions.
Upon obtaining the required information from such sources, we can determine that the estimated number of internet users today is over 5 billion. This large number reflects the widespread access to the internet across the globe, where the internet has become an integral part of daily life for a significant portion of the world's population.
Therefore, the correct answer is:
over 5 billion.
