‘Therefore’, ‘hence’, ‘thus’, ‘so’ and ‘then’ - all these expressions have one thing in common that they are all used to indicate that something that is said is a logical derivation of something that was said before. But, there are small variations between them and how and when they should be used.

‘Therefore’ is usually used to indicate scientific theories and mathematical proofs. Example:

This exhausted the oxygen inside the container. Therefore, the fore extinguished.

 

Though ‘hence’ and ‘thus’ are almost similar and often used interchangeably, there is a very slight difference between the two. ‘Hence’ is usually used to talk about a situation or a conclusion that will take place in the future. On the other hand, ‘thus’ is used to refer to something that happened in the past. For example:

The company is planning to do a lot of cost cutting. Hence, we will see many layoffs in the next few months.

It started to rain heavily. Thus, the match was called off.