What is the proper grammar usage of toward vs. towards?

Both "toward" and "towards" are grammatically correct, but "toward" is the preferred form in American English, while "towards" is the preferred form in British English. As a general rule, this also works for directional words such as "forward," "backward," "upward" and "downward."

In formal written English, it is proper to use "toward" in American English and "towards" in British English. In informal writing and speaking, however, American and British speakers and writers often use "toward" and "towards" interchangeably.

Writers used "towards" widely in American English texts until about 1900, when "toward" overtook it. Before English spelling was standardized, "toward" was common in British texts, most notably in Chaucer's "The Canterbury Tales."