Conditionals in Persian 1. - Indicative (possible)

1. Conditional clauses usually start with the condition (if clause) including the word اگر 'agar' (if) in the beginning. The 'if clause' is followed by the consequence (main clause). 

There are two main categories of conditionals: indicative (possible) and counterfactual (impossible). The current post is about the indicative conditional.

The conditional is indicative when the sentence states a possibility: thing that may happen or not; may true or not. Indicative conditionals can express different degrees of uncertainty.

A few English example:
If you heat water, it boils.
If it rains, I will stay at home.
If you are hungry, go and eat something.

2. The good news about Persian is that many combinations can be used to describe the indicative conditional correctly, however, some of them are more common than others. Let see the possibilities.

What is the difference between the three sentences?

اگر پروین بیاید من هم میایم.

Agar Parvin bi-âyad man ham mi-âyam.

اگر پروین میاید من هم میایم.

Agar Parvin mi-âyad man ham mi-âyam.

اگر پروین آمد من هم میایم.

.Agar Parvin âmad man ham mi-âyam

3. Basically there is no difference between the three sentences, however, one may say that the most common is the first one: Agar Parvin bi-âyad man ham mi-âyam. 
Moreover one may say that the possibility of "Parvin coming" is higher in the fist two cases (simple or subjunctive present) while less in the case of the usage of the past tense.

Tips for language learners: You don't need to practice all of the possibilities. You can choose the most common one to memorize and practice.

اگر این تابستان گرم باشد به مسافرت میروم.

Agar in tabestân garm bâshad be mosâferat mi-ravam.

If this summer is hot, I will travel.

اگر هر روز میوه بخورید سالم میمانید.

Agar har ruz mive bo-khorid sâlem mi-mânid.

.If you eat fruit every day, you will stay healthy

اگر بتوانم کارم را زود تمام کنم با شما به سینما میایم.

Agar be-tavân-am kâr-am râ zud tamâm konam bâ shomâ be sinemâ mi-âyam.

If I can finish my work soon, I will come to the cinema with you.

4. More examples for advanced learners
Of course, other verb forms can be also used in both part of the sentence. A few example:

اگر پروین میاید او را ببوس!

Agar Parvin mi-âyad u râ bebus!

!If Parvin comes, kiss her

اگر پروین آمده باشد با او به سینما میروم.

Agar Parvin âmade bâshad bâ u be sinemâ mi-ravam.

If Parvin has come, I will go to the cinema with her.

اگر پروین امروز آمده است چرا الان در خانه نیست؟

Agar Parvin emruz âmade ast cherâ alân dar khâne nist?

If Parvin came today, why is he not at home now?

5. The colloquial form of the word 'agar' is 'age"; otherwise, the usage is not different from the standard one.

.Age bi-ây, man-am mi-âm
.If you come, I will come too