Zero and first conditional

ZERO CONDITIONAL 

The zero conditional used when the time referred to is now or always and the situation is real and possible. This type of conditional is usually used to talk about general facts. The verb tense of both propositions is the "simple present". In conditional type 0 sentences, the term "if" can usually be replaced by "when" without changing the meaning.

FORMULA

if+simple present ,..simple present 

EXAMPLES 

1If I study too much, I get tired

2If public transport works efficient, people stop driving their cars 

first conditional 

It's used to talk about things which might happen in the future. Of course, we can't know what will happen in the future, but this describes possible things

FORMULA 

• if + present simple, ... will + infinitive

EXAMPLES 

1If it rains today, I'll stay at home.

2If it is warm tomorrow, we'll go to the beach