‘And’, ‘but’, ‘or’, and ‘so’ at the beginning of a sentence

by Jakub Marian

Tip: See my list of the Most Common Mistakes in English. It will teach you how to avoid mis­takes with com­mas, pre­pos­i­tions, ir­reg­u­lar verbs, and much more.

Most people were told at some point in their lives that starting a sentence with a conjunction is ungrammatical. Long story short, no such rule exists or has ever existed, and telling an English learner (or a native speaker, for that matter) that they should never start a sentence with a conjunction is a mistake on the part of the teacher.

There is, however, a subtle difference between a coordinating conjunction preceded by a comma and by a full stop (period). In the case of “and”, a comma implies that both parts of the sentence are equally important, while a full stop implies that the second part is just an additional “bonus”, something of interest but not as important as the first part. Compare:

You will get a new car, and you can win a lot of money.
You will get a new car. And you can win a lot of money.

Similarly, “or” preceded by a comma implies that the two alternatives are equally acceptable, whereas a full stop is often used when there is a “but”:

You can book a flight, or you can take a bus.
You can book a flight. Or you can take a bus, but that would be a long ride.

When “but” starts a sentence, it is usually used to emphasize an important disadvantage to what has been said previously. It is then often followed by a comma, which is pronounced as a pause:

Sure you can work in the Antarctic. But, it can result in your funds being frozen. [lame joke intended]

“So” is sometimes used to start a sentence (often followed by a comma) when the whole discussion has come to an end, or an important question ensues:

You must choose either life or death. So, what do you choose?

By the way, if you haven’t read my guide on how to avoid the most common mistakes in English, make sure to check it out; it deals with similar topics.