In our world, (Earth) there were 28 Buddha born with Gautama Buddha. Some people say that Maitreya Buddha is the 29th & last Buddha. My question is, in the future how many Buddhas will born.
In the Mahapadana Sutta of the Digha Nikaya, the Buddha explained some natural laws (dhammata) pertaining to the Bodhisatta Vipassi who arose in the world ninety one aeons ago. In the last 91 Kalpa (Aeons) only 7 Buddha’s have come. After Vipassi Buddha, the other six Buddhas who came were Sikhi, Vessabhu, Kakusanda, Konagamana, Kassapa and the Gautama Buddha.
A Kalpa is like Eternity. So just imagine what 91 kalpa is like. In the Anamatagga-samyutta — The unimaginable beginnings of samsara. In Samyutta ii, Chapter XV, the Buddha used the parables of the hill and mustard-seed for comparison:
Suppose there was a solid mass, of rock or hill, one yojana (eight miles) wide, one yojana across and one yojana high and every hundred years, a man was to stroke it once with a piece of silk. That mass of rock would be worn away and ended sooner than would an aeon.
Suppose there was a city of iron walls, one yojana in length, one yojana in width, one yojana high and filled with mustard-seeds to the brim. There-from a man was to take out every hundred years a mustard-seed. That great pile of mustard-seed would be emptied and ended sooner than would an aeon.
At the time of the next Buddha, the average lifespan of a human is going to be eighty thousand years. (In the present day it is around 60 -80 years). There will not be any more Buddhas for many a aeon, after the next, as per the scriptures.
There are 28 Buddhas described in the Buddhavamsa. Our Gautama Buddha first obtained “niyata vivarana” that he will definitely become a Buddha in the future, from Buddha Dipankara, who was the 24th Buddha preceding Buddha Gotama.