noun
Refers to how fast something moves or happens. Often used with 速さ.
この車の速さは時速200キロを超える。
This car's speed exceeds 200 kilometers per hour.
彼の仕事の速さには驚かされる。
I'm amazed at the speed of his work.
noun
earliness
Refers to how early something occurs. Typically written as 早さ.
彼の出社の早さは誰にも負けない。
No one beats him when it comes to how early he arrives at work.
今年の梅雨入りの早さは記録的だ。
The earliness of this year's rainy season onset is record-breaking.
Adjective meaning 'fast' or 'quick'. 速さ is the noun form expressing the degree of speed.
Adjective meaning 'early'. 早さ is the noun form expressing the degree of earliness.
Noun form of the adjective はやい (fast/early), created by replacing the final い with さ to express degree or -ness.