Is “I spelled it correct” correct grammar?

Both are correct. One is a typical British spelling and the other is American. So, depending on where you live, going with the one that is familiar to the 'locals' will generate less confusion. read more

In the sentence “I spelled it correct,” “correct” is an adverb, that is, it modifies a verb. In this case, it modifies “spelled.” The adverbial form is “correctly.” So you have “I spelled it correctly.” “Spelled” is the American form and “spelt” refers to a type of wheat. read more

Spelled and Spelt The verb to spell most commonly means to write or name the letters that form a word in correct sequence. To spell is one of those verbs with both an irregular form and a regular form. read more