Holocene calendar

calendar era that uses 10,000 BC as 1 HE

The Holocene calendar, or Human era (HE), is a year numbering system that adds 10,000 years to the present Anno Domini (AD) or Common Era (CE) system. It puts the first year near the beginning of the Holocene epoch and the Neolithic revolution. Those who favour the HE system say that it makes for easier geological, archeological, dendrochronological and historical dating.

For example, the year 2022 can be made into a Holocene year by adding the number "1" before it, making it 12022 HE. The calendar was introduced by the scientist Cesare Emiliani in 1993 (11993 HE).[1][2][3]

Arguments supporting the Holocene calendar include:

  • In the Anno Domini system the birth of Jesus represents the year 1. People now think Jesus was born four years earlier.
  • The years BC are counted down when moving from past to future, making it more difficult to calculate timespans across this divide.
  • The Anno Domini system has no year zero, with 1 BC followed by year 1. It is important to not forget this when calculating lengths of time.

The HE starts at 10001 BC. This is a rough approximation of the start of the current geologic epoch, the Holocene or Recent period. Human settlements, first cities and agriculture probably started in this period. All important dates in human history can then be listed using a simple increasing date scale with smaller dates always before larger dates.



Conversion to the Human Era from Julian or Gregorian AD years can be achieved by adding 10,000. BC years are converted by subtracting the BC year from 10,001.

A useful check is that the last single number of BC and HE equivalent pairs must add up to 1 or 11.

Gregorian years ISO 8601 Human Era
Holocene Epoch
30001 BC −30000 20000 BHE
10001 BC −10000 0 HE
10000 BC −9999 1 HE Beginning of Holocene.
9001 BC −9000 1000 HE
1000 BC −0999 9001 HE
753 BC −0999 9248 HE Foundation of Rome.
100 BC −0099 9901 HE Birth of Julius Caesar.
10 BC −0009 9991 HE
4 BC −0003 9997 HE Birth of Jesus.
2 BC −0001 9999 HE
1 BC +0000 10000 HE
1 +0001 10001 HE
2 +0002 10002 HE
10 +0010 10010 HE
33 +0033 10033 HE Crucifixion of Jesus.
100 +0100 10100 HE
632 +0632 10632 HE Death of Muhammad.
1000 +1000 11000 HE
1582 +1582 11582 HE Adoption of Gregorian calendar.
2000 +2000 12000 HE
Current year
10000 +10000 20000 HE Y10K problem.
  • Common Era
  • Julian date (JD) – the interval of time in days and fractions of a day since January 1, 4713 BCE, Greenwich noon.


  1. Cesare Emiliani, "Calendar Reform", Nature 366 (1993) 716.
  2. The Holocene Calendar at Meerkat Meade.
  3. Harry Weseman. "Human Era Calendar". Archived from the original on 2014-11-29. Retrieved 2014-03-02.