One billion seconds is 31.69 years or a little more than 11,574 days. In the context of a human lifespan, I will personally cross the one billion second threshold around dinner time on May 2nd, 2021. Jean Calment holds the record for individual longevity, clocking in at an impressive 3.86 billion seconds of life. To put that in context, Calment's lifespan covers more than 1% of the total longevity of human civilization, which has been around for roughly 378 billion seconds.