On is used to indicate location or position on a surface. Onto indicates the movement of something from a particular position or location to another. On to, as two words, are used when on is a part of a phrasal verb. Prepositions are an integral part of the English language. They show the relationship between other words in a sentence. Though most prepositions express very specific ideas, many of them are close in their meaning and spelling. These overlaps often confuse writers, leading to incorrect word choices. On, onto and on to are three such confusing prepositions that are used interchangeably by many, but they do not exactly mean the same! So what is the difference between these three words? How do they change the meaning of the sentence? And most importantly, which preposition should be used where? We will answer all these questions today and help you get them right in your writing.