if I was, if I were

Use the subjunctive in a clause introduced by if (e.g. if he were) when the clause expresses a hypothetical situation that is unlikely or clearly not true.

• If he were riding his bike, I would have seen him go by my window. But I didn’t.
• If I were you, I wouldn’t take that job.

Use the indicative in a clause introduced by if (e.g. if he was) when the clause describes something factual or likely to happen.

• If he was outside when the storm struck, he must have gotten wet.
• If Sue was hoping to win the prize, she’s going to be disappointed.