Thus vs. Therefore vs. Hence vs. So – Difference Explained

There are several ways to link an English statement to a consequence or an event following that action. Four of the most common are “thus”, ”therefore”, ”hence”, and “so”. They provide a similar function, but do they have exactly the same meaning? Let’s have a closer look.

Thus vs. Therefore vs. Hence vs. So

“Thus” and “so” have similar applications, but “so” is used much more often, and in a wider range of contexts.  Similarly, “hence” and “therefore” convey similar meanings, with “therefore” occurring much more frequently, and “hence” limited to more formal speech.

thus vs therefore vs hence vs so

In many instances, “so” and “thus” can be employed interchangeable. However, a notable exception is in the common phrase “so that”, meaning “in order for (the following) to happen”.

The phrase “thus that” does not exist.    Similarly, “hence” and “therefore” are often interchangeable, although “therefore” is, by far, the most commonly used.


“Thus” can be described by the phrase “for that reason” or “in this way” or “up until”. This means that it is similar to “so”, but it is seldom used in everyday speech, as it sounds more archaic or academic. It is more often found in polite and formal written English.

 Like “so”, “thus” may be used to describe something you are pointing to or demonstrating physically

Let’s look at how “thus” can be used in a sentence.

  1. He has been able to demonstrate his competence and his devotion to duty in all the tasks assigned to him thus far.
  2. He stood in front of his pupil and showed him how to grip the club,” Place your left hand over your right hand, thus.”
  3. When they first met, they discovered a shared sense of humour; thus began a firm friendship that was to last a lifetime.
  4. He stood up, turned around and left the room, without so much as a polite excuse; thus bringing the conversation to an abrupt halt.
  5. The product had been designed with convenience and economy in mind, and thus was to be found in almost every supermarket.
  6. Her office will be located in the centre of London, thus requiring a two-hour commute from her home in the country.
  7. Drinks were served at the entrance to the concert hall, thus eliminating the need for an interval during the performance.


“Therefore” is used when deduction is reached from the preceding information. Another way to say it might be that the conclusion reached is “a consequence of” the preceding information. This makes it the preferred choice in cases of mathematics, science, or logical reasoning.

 It is frequently heard in everyday conversation when explaining or justifying reasoning.

Here are some examples which highlight the meaning and how to use “therefore” in a sentence:

  1. Jack is twice as old as Jill, and Jill is 25, therefore Jack must be 50 years old.
  2. The detectives are satisfied that the waiter was working in the restaurant until 11pm, therefore he could not be the murderer.
  3. The drugs can cause tiredness, therefore I don’t recommend that you take them when you are driving or operating machinery.
  4. There has been no rain in the area for more than six weeks and the ground is dry, therefore all fires are prohibited until further notice.
  5. I was born on the 29th of February, therefore I only get the chance to celebrate my birthday every four years!


The word “hence” is used to mean “from now” or “from this time”. It is older, more formal language, and it is rarely used in everyday speech. When used in formal and/or written speech, it is often linked to “forward” or “forth” to give “henceforward “ and  “henceforth”, meaning “from now on”.

Here are some examples of how “hence” can be used in a sentence:

  1. His position as king was weak and he felt threatened by the neighbouring kingdoms; hence the need to recruit and train an elite army.
  2. The trees had all been chopped down to produce firewood; hence the lack of shade on the island.
  3. The newspapers have decided to merge and shall henceforth be known as “The Evening Mail”.
  4. It had rained constantly for three days, hence the decision to hold the event indoors.
  5. Due to the high demand for tickets this year, we declare that the event shall henceforward be held in the Town Hall.
  6. He has always liked to spend most of his time out of doors, hence his decision to take the job in the country.


“So” has the broadest range and is the most frequently used. It can mean “like this” or “in this manner”, especially when demonstrating an action or example. It is also used in the same way as “therefore” to make a deduction. “So far”, like “thus far” means “up until now”.

“So” can also be combined with “that” to give “so that”, which is commonly used to mean “in order to” or “as a consequence of” or “therefore”. “So” has many uses and is frequently used, especially in speech. Here are some ways to use “so” in a sentence:

  1. She gave up her job so that she could spend more time at home with her children.
  2. He has an Irish passport and so he doesn’t need a visa to enter The Netherlands.
  3. Could you tell me where I could find a piece of wood to fit this frame like so?
  4. They have fielded the most consistent team in the league so far this season.
  5. They built a fence around the garden so that the children could play outside in safety.
  6. The doctor has received an emergency call to attend a seriously ill patient, and so she will not be joining us for dinner this evening.
  7. So, have you decided when you will book the flight to New York?

Which Is Most Formal?

“Thus” and “hence” are most formal, and are not commonly found in casual speech. They are more likely to be used when academic or official language is appropriate. “So” and “hence” can be found in formal reports or records, or in official speech.

If in doubt, leave them out! As “thus” and “hence” can be easily replaced by “so” or “therefore”, respectively, there is seldom a need to use them. You only need to be able to recognize them, understand the meaning, and discern when the speaker is employing a more formal register.

Which Is Less Formal?

The word “so” is the least formal and the most versatile. It can be found in both formal and informal language. “So” can be used in most contexts, and it is heard very frequently. An added advantage is that it always sound warmer than using “hence” or “thus”.

“So” is useful when you want to relate a sequence of events, and it is a common device to link events or facts when expressing your reasoning or motive. It can even be used to replace “therefore” in sentences where logical deduction is applied.

So, “so” is one of the most useful tools at your disposal!

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