The core, simple formula for a percentage is
The term evolved over time. "Per" was often abbreviated to "p", and "cento" was contracted until it eventually became the modern symbol: %. per centum
The phrase emerged from per centum (16th century), and its usage was heavily refined by Italian merchants, who frequently used "per cento" for calculating taxes, interest, and discounts. The core, simple formula for a percentage is
Parts per 10,000 (one-hundredth of 1 percent). Per Cent Mille (pcm): Parts per 100,000 (1 in 100,000). Parts per 10,000 (one-hundredth of 1 percent)
A percentage breaks down any quantity into 100 parts, making it a standardized metric for comparison.
If a whole is divided into 100 parts, a "percentage" indicates how many of those parts make up the subset being discussed.
The term is conceptually identical to one "cent" being 11001 over 100 end-fraction of a dollar, thus 37 cents is 37 percent of a dollar. Deep Mathematical Meaning