In Order To vs. So As To

We often use an infinitive to talk about a person’s purpose.

• He rose to speak.
• She came to the city to look for work.
• He sat down to rest.

We can also use in order to or so as to.

• She came to the city so as to look for work.

So as to and in order to are more common before verbs like be, have, know etc.

• He raised his voice so as to be heard.
• He got up early in order to have enough time to pack.

Before a negative infinitive, we normally use so as or in order.

• I am leaving now so as not to be late. (NOT I am leaving now not to be late.)