Geological Time

Geological periods and time scale covering the Cenozoic, Mesozoic, Paleozoic, and Pre-Cambrian eras.

Geological Time

Geological periods and time scale with major events and evolutionary milestones.

Overview

This tool provides a comprehensive reference for geological time periods, from the present day (Holocene) back to Earth's formation (Hadean). Each period includes the time range in millions of years and significant evolutionary or geological events.

Era	Period/Epoch	Beginning - End (10⁶ years)	Significant Events
Cenozoic	Holocene	0 - 0.0115	Present day
Cenozoic	Pleistocene	0.0115 - 1.81	Homo erectus - evolution of anatomically modern humans
Cenozoic	Pliocene	1.81 - 5.3	First recognizable hominins (australopithecines)
Cenozoic	Miocene	5.3 - 23	Origin of grass
Cenozoic	Oligocene	23 - 34	Rise of cats, dogs, pigs
Cenozoic	Eocene	34 - 56	Hoofed animals
Cenozoic	Paleocene	56 - 65	Primates
Mesozoic	Cretaceous	65 - 145	Demise of dinosaurs
Mesozoic	Jurassic	145 - 200	First birds
Mesozoic	Triassic	200 - 251	Many major groups of dinosaurs emerged
Paleozoic	Permian	251 - 299	Flowers, insect pollination
Paleozoic	Carboniferous	299 - 359	First conifers
Paleozoic	Devonian	359 - 416	First vertebrates ashore
Paleozoic	Silurian	416 - 444	Spore-bearing plants
Paleozoic	Ordovician	444 - 488	Vertebrates appear
Paleozoic	Cambrian	488 - 542	Most animal life aquatic
Pre-Cambrian	Proterozoic (Pre-Cambrian III)	542 - 2500	First advanced single-celled eukaryotes, multi-cellular life, first plants, jellyfish
Pre-Cambrian	Archean (Pre-Cambrian II)	2500 - 3850	Photosynthetic bacteria
Pre-Cambrian	Hadean (Pre-Cambrian I)	3850 - 4600	Earth formed 4600 million years ago

Calculator

Inputs

Period Start (million years ago) (Mya)

Period End (million years ago) (Mya)

Results

Period Duration-- million years

Percentage of Earth History-- %