What is the difference between “so” and “so that”?

What is the difference between “so” and “so that”?

Both of these words are adverbs.  They are used with a subject and a verb to make a clause.  “So that” tells us for what purpose something is done.  What was the intention or plan?  In contrast, “so” tells us the effect.  It tells us what happened as a result.

For example:
  • I am writing this blog so that I can explain the difference between these two words.  
    • [adverb = so that,  subject = I,  verb = can explain]
  • So that I can explain the difference between these two words, I am writing this blog.  
    • [adverb = so that,  subject = I,  verb = can explain]
  • Explaining grammar can be tricky, so I will try to use easy examples.
    • [adverb = so,  subject = I,  verb = will try]

Notice how “so” is preceded by a comma (,) but “so that” is not.

The clause with “so that” can come both before and after the independent (or main) clause, whereas “so”cannot change positions but must remain in between both clauses.

Broken Arm

This girl has her arm in a cast.

Why did the doctor put the girl’s arm in a cast? 

The doctor put her hand in a cast so that her bones could heal.

He put the cast on tightly so that her arm wouldn’t move around.

What is the effect of having a cast on her arm?

Her cast is hot, so it makes her arm sweaty and itchy.

Her cast isn’t waterproof, so she can’t get it wet.

Her bones are healing, so she isn’t supposed to bump her cast into anything.

Students at PELA

These students are studying English in the U.S.

Why are these students studying English?  What is their purpose?

One is studying English so that he can go to an American university.

Another is studying English so that she can travel.

A third is studying English so that she can get a better job.

The fourth is studying English so that he can find an American girlfriend.

What is the result of their studying English in the U.S.?  What are the effects of their being here?

They are living in an English-speaking country, so they hear English every day.

They are students, so they have homework and must practice.

All of them speak different native languages, so they must use English to understand one another.

Barking Dog

Many people buy watchdogs.

What is the purpose of watchdog dogs?

People buy watchdogs so that no one will rob them.

They buy watchdogs so that they feel safe.

What are the effects of having this kind of dog?

The dogs are scary, so strangers keep their distance.

The dogs can be dangerous, so the owners must keep them behind a fence or on a chain.



  1. Why do you password protect your phone? (so that)
  1. If it has a password, what happens if someone steals it? (so)
  1. Why do some women wear makeup? (so that)
  1. Some makeup isn’t waterproof. What happens when it rains?  (so)
  1. Why do many of us exercise? (so that)
  1. You exercise regularly. What happened the last time that you went to the doctor?  (so)

(possible answers below)

  1. I password protect my phone so that no one can use it without my permission.
  2. It has a password, so they won’t be able to open it.
  3. They wear makeup so that they will feel more beautiful.
  4. It’s not waterproof, so it runs.
  5. We exercise so that we will be fit and healthy.
  6. I exercise regularly, so my blood pressure was low.