scroll
click
to jump
Key ⠿ drag minimize
Bars and events, left to right
Geologic time bars
Eon Era Period Epoch Age Cenozoic Mesozoic Paleozoic Proterozoic Archean Cenozoic Mesozoic Paleozoic Neoproterozoic Mesoproterozoic Paleoproterozoic Q N Pg K J
Float cursor over any bar → eon · era · period · epoch · age
O₂ level (atm)
Float cursor → O₂ percentage
CO₂ × present
Float cursor → CO₂ in PPM
Evolutionary event
Mass extinction
Geologic event
Human evolution event
Click any marker to expand
Time scale: International Commission on Stratigraphy

About Linear Scale

On the linear scale all 4.5 billion years are shown proportionally — but most of Earth's recorded life sits in the final 1%. To keep event labels readable, collision detection automatically spreads overlapping markers apart. This means an event dot may sit slightly above or below its true proportional position on the time-period bars to the left.

Hover over any marker to see its exact age, or click it to open its information pane.