Buy Something on Installments vs. In Installments: US vs. UK English

'Buy sth. on installments' and 'Buy sth. in installments' are both used to describe purchasing something with the option of paying for it in multiple installments over a period of time. The difference between the two phrases lies in their prepositions.

In American English, 'on' is commonly used to indicate the method of payment or terms of a purchase. Therefore, 'Buy sth. on installments' is the more commonly used phrase in American English.

In British English, 'in' is often used to indicate the method or manner of a transaction. Therefore, 'Buy sth. in installments' is the more commonly used phrase in British English.

However, it is important to note that both phrases are generally understood in both countries and can be used interchangeably to convey the same meaning.