The Bible does not clearly specify an allotted life span. There are two Bible passages that are sometimes quoted in connection with human lifespans.
“My Spirit shall not abide in man forever, for he is flesh: his days shall be 120 years.”
Here God is commenting on the future of the human race. The passage has been interpreted to mean that God placed a limit of 120 years on human lifespans that was gradually introduced after the flood (See “Why did people live so long before the flood?”). However, it is more likely that the sentence simply means that there were 120 years until God would send the flood.
Our days may come to seventy years,
or eighty, if our strength endures;
yet the best of them are but trouble and sorrow,
for they quickly pass, and we fly away.
In this verse, the writer is describing what he had observed — that people tended to live to about 70 or possibly 80 years. It is not a promise, or an allocated lifespan.