Free Spanish grammar checker that explains why a sentence changed

Office spellcheckers were built for native speakers who mistype a keystroke or forget a written tilde on sábado. When an A2 or B1 learner writes “estoy caliente” to say they feel warm, or “busco por mis llaves” translating English “look for” word by word, every individual word exists in the Spanish dictionary—so a basic spelling tool marks the sentence green.

An effective Spanish grammar check has to evaluate sentence structure, verb mood, and English calques together. When you run a sentence through the checker at the top of this page, it compares your draft against natural spoken Spanish, strikes out only the words that need to change, and writes a one-sentence note naming the exact rule (such as why “buscar” already includes the meaning of “for” and takes no preposition).

Three patterns account for most intermediate corrections. First is the boundary between indicative and subjunctive: clauses after “quiero que”, “es importante que”, “no creo que”, or time conjunctions pointing to the future (“cuando llegues”) require subjunctive stems that learners rarely catch on their own. Second is choosing between preterite and imperfect when telling a story about yesterday.

Third is pronoun placement and redundancy, such as remembering indirect “le” or “les” alongside a named person (“Le dije a Marta”) and ordering double pronouns as “se lo” rather than “le lo”. Testing your own sentences in a Spanish grammar checker online before or during study sessions turns vague textbook rules into concrete edits you can immediately see.