The Lifespan of the Buddha

In certain kalpas, the lifespan of a Buddha and the lifespan of sentient beings are both very long, measured in kalpas. One small kalpa is 16.8 million years; a Buddha's lifespan can be manifested as twelve small kalpas, or even longer, depending on the wholesome karma accumulated by the Buddha when He was a bodhisattva, and also on the karmic power of sentient beings. But this is only a manifestation; the actual lifespan of a Buddha is one of immeasurable longevity, which can be infinitely long and is not limited by time. Shakyamuni Buddha's lifespan in this Saha world was eighty years, similar to the hundred-year lifespan of sentient beings at that time; this was determined by the karmic power of sentient beings. Shakyamuni Buddha could have remained in the Saha world for more than a kalpa, but sentient beings lacked the merit to attract such a supremely excellent retribution, and the Buddha's remaining longer in the world would have brought no benefit to Buddhism or to sentient beings; therefore the Buddha manifested an eighty-year lifespan in accordance with conditions.