They have the same meaning but it's a matter of sense However, there are some sentences that you can't use only instead of just, Let's see: I have just one apple/ I have only one apple No problem here but for: I have just came for 2 minutes , Not to say I have only came for two minutes!! It goes like that, and by practice you will get that sense

I'm sorry to say that it's actually very complicated....like many things about English! Both words can function as adjectives, which modify nouns (things), and they can also function as adverbs, which modify verbs (actions). I'm just going to give some common examples: ADJECTIVES: 1a. Baby, you are the <only girl> I love. - YES 1b. Baby, you are the <just girl> I love. - NO!! Although the word "just" CAN be an adjective, it is relatively rare, since it will mean things like "correct", or "fair", or "right", related to the word "justice". So, let's skip "just" as an adjective for now. But "only" is commonly used in English as an adjective, meaning "one or very few of a kind". 2. Morocco is the <only country> I have visited in Africa. - YES 3. The <only sport> I play is tennis. - YES 4. Ladies and gentlemen, here is the <one and only Rafael Nadal!> - YES ADVERBS: This is where "just" and "only" can be *nearly* the same, but not exactly. They are nearly interchangeable when the meaning is "no more than", or "merely": 1a. I <only need> my health, food, shelter and love to be happy. - YES 1b. I <just need> my health, food, shelter and love to be happy. - YES 2a. I'm too tired to go out drinking; I <only want> to sleep. - OK 2b. I'm too tired to go out drinking; I <just want> to sleep. - YES 3a. Why are you mad at me? I was <only trying> to help. - YES 3b. Why are you mad at me? I was <just trying> to help. - YES The most common use for "just" is probably when it means "very recently": A. I'm very full, because I <just ate> a whole chicken. B. Tomas can't come to the phone right now; he <just left> for work. C. <Just married!> (Commonly written on newlyweds' cars.) As I say, it's very complicated, and there are many more exceptions. If you would like to try writing some sample sentences with "only" and "just", I'd be happy to help correct any mistakes in usage.

some examples of using just he had just enough money to pay the bus fare he got there just in time if he had just listened to my advice it would have worked out she has just arrived some examples of only he only had two apples left (or, he had only two apples left) he was the only one there he only had enough money to buy one bus ticket (he had enough money to only buy one bus ticket) if only he had listened to me there were only six people at the meeting I can only stay for a few minutes