In general, “if it was possible” and “if it were possible” are both correct, but in different contexts. “if it was possible” is used to refer to things that could actually happen, while “if it were possible” is used to refer to things that are more hypothetical.
Let’s explore the differences between the two to clear up when and how to use each one, and whether you can swap them out in a sentence.
“If it were possible” and the Subjunctive Mood
The phrase “if it were possible” is part of a very small subset of English grammatical tense called the subjunctive mood. This tense is used to talk about situations or things that are hypothetical, or that haven’t or couldn’t happen but are being considered from an academic perspective. For instance:
if it were possible to go to Jupiter, I would go in a heartbeat.
if it were possible to fly, that would be so cool.
“If it was possible” and the Plausible Past
On the other hand, when referring to something that may have actually happened, you would use “if it was possible.” There’s no official grammatical term for this context, but a good way to think of it is as the plausible past. For example:
If it was possible to visit you in hospital, I would have done so.
if it was possible to change the date, we would have come.
This version of the phrase is used when talking about a real situation without giving a specific instance (such as in the first example) or in a case where it’s unclear whether the past action or situation actually occurred (such as in the second or third examples).
“If it were possible” and “if it was possible” difference?
The difference between “if it were possible” and “if it was possible” is that when we use “were”, we are describing a more hypothetical situation and when we use “was”, we are describing a more plausible situation.
If it were possible to change the date of the wedding that would be amazing.
If it was possible to change the date of the wedding that would be amazing
As you can see, in some contexts both options could be correct. It just depends on the speaker’s belief about whether something is possible or not.