Which is correct, "canceled" or "cancelled"?

Answer 1

I think dictionaries give both spellings for past tense as correct, but if you go by pronunciation rules, it's the first — the one with one "l" — because there is no stress on the syllable -cel.

The same with benefit — except that -tted is considered incorrect. There is no stress on the syllable -fit and therefore the past is spelled "benefited."