English ‘while’ and ‘whilst’
Both of these words have the same meaning and can be used interchangeably.
Some dictionaries deem whilst as an older or archaic version thus obsolete/deprecated. However, it’s still quite popular in academic, formal text or poetic writing.
Certain sources proclaim that in times of Middle English, the suffix -s was often appended to words in order to indicate the use of an adverb e.g. an even less common whiles. As the English language evolved, confusion arose and superlatives started to mismatch thus causing conversion of –s endings to –st.
Using while you won’t ever be wrong, whereas whilst can easily look out of place.
From purely geographical perspective, while is commonly used across all countries whereas whilst mainly in British. Though, more in writing than speech presumably due to its pronunciation.