4.54 billion years in one year
Deep time calendar
If Earth formed at midnight on 1 January, the dinosaurs died out on 26 December and our own species turned up at 23:25 on New Year's Eve. This calendar squeezes Earth's 4.54 billion years into one year, and lays the same history along a walk, a football pitch or a toilet roll of any length.
The whole year
31 December, hour by hour
Along a 4.54 km walk, every metre stands for 1 million years and every foot for 304,800 years. On the calendar each day is 12.44 million years and each second about 144 years.
| Event | When | On the calendar | Along a 4.54 km walk |
|---|---|---|---|
| 1Earth forms4.54 billion years ago, uncertain by less than 1 percent. USGS, Age of the Earth | 4.54 billion years ago | 1 January, 00:00365 days before the year ends | 0 m 0 ft from the start4.54 km (2.82 mi) before the end |
| 2Oldest known mineral grainA zircon from the Jack Hills, Western Australia: 4,404 ± 8 million years. Wilde et al. 2001, Nature 409:175 | 4.404 billion years ago | 11 January, 22:24354.1 days before the year ends | 136 m 446.2 ft from the start4.4 km (2.74 mi) before the end |
| 3Earliest convincing signs of lifeMicrobial structures in the ca. 3.48-billion-year-old Dresser Formation, Western Australia. Older claims, such as 3.7-billion-year-old structures in Greenland, are disputed. Djokic et al. 2017, Nature Communications 8:15263 | 3.48 billion years ago | 27 March, 05:17279.8 days before the year ends | 1.06 km 3,477.7 ft from the start3.48 km (2.16 mi) before the end |
| 4Great Oxidation EventOxygen first builds up in the atmosphere, about 2.43 billion years ago. Poulton et al. 2021, Nature 592:232 | 2.43 billion years ago | 19 June, 15:16195.4 days before the year ends | 2.11 km 1.31 mi from the start2.43 km (1.51 mi) before the end |
| 5First large complex fossilsEdiacaran fossils of the Drook Formation, Newfoundland: 574.17 ± 0.66 million years. Matthews et al. 2021, GSA Bulletin 133:612 | 574.17 million years ago | 15 November, 20:0746.2 days before the year ends | 3.97 km 2.46 mi from the start574.2 m (1,883.8 ft) before the end |
| 6Cambrian Explosion beginsBase of the Cambrian, 538.8 ± 0.6 million years ago, when most major animal groups appear. ICS chart v2026/06; UC Museum of Paleontology | 538.8 million years ago | 18 November, 16:2243.3 days before the year ends | 4 km 2.49 mi from the start538.8 m (1,767.7 ft) before the end |
| 7First land plantsThe earliest generally accepted spores of land plants, about 475 million years old (Middle Ordovician). Wellman et al. 2003, Nature 425:282 | 475 million years ago | 23 November, 19:2838.2 days before the year ends | 4.07 km 2.53 mi from the start475 m (1,558.4 ft) before the end |
| 8End-Permian mass extinctionThe largest extinction in the history of life, between 251.941 and 251.880 million years ago. Burgess et al. 2014, PNAS 111:3316 | 251.9 million years ago | 11 December, 17:5720.3 days before the year ends | 4.29 km 2.66 mi from the start251.9 m (826.4 ft) before the end |
| 9First dinosaursSome 230 million years ago, in the Late Triassic. Martínez et al. 2011, Science 331:206 | 230 million years ago | 13 December, 12:1218.5 days before the year ends | 4.31 km 2.68 mi from the start230 m (754.6 ft) before the end |
| 10Charmouth's ammonitesThe cliffs at Charmouth on the Jurassic Coast were laid down around 195 million years ago. Charmouth Heritage Coast Centre | 195 million years ago | 16 December, 07:4415.7 days before the year ends | 4.35 km 2.7 mi from the start195 m (639.8 ft) before the end |
| 11End-Cretaceous mass extinctionThe Cretaceous–Paleogene boundary, 66.00 million years ago: the non-bird dinosaurs and the ammonites die out. ICS chart v2026/06; Natural History Museum, What is an ammonite? | 66 million years ago | 26 December, 16:395.3 days before the year ends | 4.47 km 2.78 mi from the start66 m (216.5 ft) before the end |
| 12Megalodon disappearsExtinction at the early–late Pliocene boundary, about 3.6 million years ago. Boessenecker et al. 2019, PeerJ 7:e6088 | 3.6 million years ago | 31 December, 17:03:136.9 hours before midnight | 4.54 km 2.82 mi from the start3.6 m (11.8 ft) before the end |
| 13Earliest members of our genus, HomoA jaw from Ledi-Geraru, Ethiopia, 2.80 to 2.75 million years old. Villmoare et al. 2015, Science 347:1352 | 2.8 million years ago | 31 December, 18:35:505.4 hours before midnight | 4.54 km 2.82 mi from the start2.8 m (9.19 ft) before the end |
| 14Homo sapiensOur species appears about 300,000 years ago; fossils from Jebel Irhoud, Morocco, are 315,000 ± 34,000 years old. Smithsonian Human Origins Program; Hublin et al. 2017, Nature 546:289 | 300,000 years ago | 31 December, 23:25:1634.7 minutes before midnight | 4.54 km 2.82 mi from the start30 cm (11.8 in) before the end |
| 15Last ice sheets at their largestNearly all ice sheets were at their maximum from 26,500 until 20,000 to 19,000 years ago. Clark et al. 2009, Science 325:710 | 26,500 years ago | 31 December, 23:56:563.1 minutes before midnight | 4.54 km 2.82 mi from the start2.7 cm (1 in) before the end |
How the deep time calendar works
The year starts with Earth's formation, 4.54 billion years ago, and ends at midnight on 31 December, today. Each event's date is simply how far through Earth's history it happened: 66 million years ago is 98.5 percent of the way through, which is 26 December. Every day of the calendar stands for about 12.4 million years and every second for about 144 years, so the 300,000 years of our own species fit into the last 35 minutes.
The line works the same way. On the 4.54 km walk each metre is one million years: the Cambrian Explosion begins only 539 m from the end, and the peak of the last ice age is the final 2.7 cm. On a 100 m pitch, megalodon disappears 8 cm before the goal line. For a toilet roll, count the sheets and measure one, and every sheet becomes millions of years.
Print the page for a classroom or a beach walk: the buttons and menus are left off the printout.
Sources
Earth's age, 4.54 billion years with an uncertainty of less than 1 percent: USGS, Age of the Earth. Each event in the table links to its own source: peer-reviewed papers (Wilde et al. 2001; Djokic et al. 2017; Poulton et al. 2021; Matthews et al. 2021; Wellman et al. 2003; Burgess et al. 2014; Martínez et al. 2011; Boessenecker et al. 2019; Villmoare et al. 2015; Hublin et al. 2017; Clark et al. 2009), the ICS chart v2026/06, the Smithsonian, the Natural History Museum and the Charmouth Heritage Coast Centre.
Questions
If Earth's history were a year, when would humans appear?
Homo sapiens, about 300,000 years ago, arrives at 23:25 on 31 December, about 35 minutes before midnight. The first members of our genus, 2.8 million years ago, arrive at 18:35 the same day.
When would the dinosaurs live on the calendar?
The first dinosaurs, some 230 million years ago, appear on 13 December; they die out with the ammonites on 26 December, 66 million years ago.
Why does the year start with 4.54 billion years?
That is the age of the Earth from meteorites and lead isotopes, given by the USGS with an uncertainty of less than 1 percent.