Human lifetime
A human lifetime is the span from a person's birth to their death.
How big is it?
80 years
Time · reference interval
A little perspective
A century is about 1.25 times larger on this measurement.
A century: A century is a period of one hundred years.
Measurements, assumptions & sources +
Human lifetime
An 80-year comparison interval, not a prediction of life expectancy.
Defined examples — our methodology
The marked time is calibrated. Unmeasured illustration details are representative.
A century
One hundred Julian years for consistent conversion.
Defined examples — our methodology
The marked time is calibrated. Unmeasured illustration details are representative.
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Why this measurement?
Why we use 80 years
For comparison, this page uses time. This is labelled reference interval: an explicit comparison model rather than a claim that every example has the same value.
An 80-year comparison interval, not a prediction of life expectancy.
The identifying illustration and the numerical comparison remain separate. How calibrated comparisons work →
Recorded properties
Human lifetime dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 80 years | Not recorded | reference interval |
Around this scale
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These links use compatible time records, ordered around the selected value.
Sources and method
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The source records and measurement method remain available for inspection.
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
TimeBlink of an eye150 msA blink of an eye is the quick closing and opening of the eyelid, usually happening involuntarily.
TimeAge of Earth4.54 GyrThe age of Earth is the time that has passed since the planet formed from the solar nebula.TimeAge of the universe13.8 GyrThe age of the universe is the time since the Big Bang, marking the beginning of cosmic expansion.TimeA century100 yearsA century is a period of one hundred years.TimeRecorded-history interval5 kyrThe recorded-history interval is the span for which humans have kept written or documented records.
PeopleRed-cell lifespan120 daysRed-cell lifespan is the average time a human red blood cell remains in circulation before being removed from the bloodstream.
TimeVenus solar day116.8 daysA Venus solar day is the interval between two successive sunrises at the same location on Venus, which is much longer than an Earth day.TimeMoon phase synodic cycle29.53 daysThe Moon phase synodic cycle is the average time between identical lunar phases, such as from one full moon to the next.