The phrase "are on a par with" is a common idiom that means two things are equal or similar in comparison. There are many synonyms for this expression, including "are equivalent to," "are comparable to," "are of the same standard as," and "are evenly matched with." Other options include "are in keeping with," "are in parallel with," "are in line with," and "are commensurate with." Regardless of the phrasing used, these synonyms convey the idea that two things are equal or similar when compared to one another. Choosing the right synonym can help to add variety and nuance to your writing or conversation.