Even if/Even though

From LEARN ENGLISH TODAY:

EVEN THOUGH

Even though is used to express a fact, something that is real or true.

'Even though' means 'despite/in spite of' the fact.
It is more emphatic or stronger than 'though' or 'although'.

• Even though John is rich, he lives in a small house.
  (John is rich, but despite having money he lives in a small house.)
  
• Even though she likes animals, Mary doesn't want a dog.
  (Mary likes animals, but in spite of that she doesn't want a dog.)
  
• Even though the building was damaged, business went on as usual.
  (The building was damaged, but despite that business went on as usual.)
  
• Even though I washed it several times, I couldn't get rid of the stain.
  (I couldn't get rid of the stain despite washing it several times.)

EVEN IF

Even if is used in a supposition or hypothesis.
It refers to an imaginary or unreal situation.

• Even if Caroline earned a big salary, she would not buy a fast car.
  (Supposing Caroline earned a big salary. She still wouldn't buy a fast car because she thinks they are too dangerous.)
  
• Even if I had time and money, I still wouldn't go on a cruise.
  (Supposing I had time and money. I still wouldn't go on a cruise. I have other reasons for not going.)
  
• I wouldn't wear that dress even if I got it for free!
  (Imagine getting that dress for nothing. I still wouldn't wear it!)
  
• Even if Tom was offered a job in New York, he wouldn't accept it.
  (Supposing Tom was offered a job in New York. He wouldn’t accept it because he doesn't like big cities.)