The difference between "if it were" and "if it was" ?

I believe that using “were” would be more appropriate in situations where the event did not happen, or is simply just a possible event, whereas “was” is technically reserved as the 1st or 3rd person singular past tense of the verb “to be.”

However, language is always changing, and speaking as a native English speaker in America, saying “if the interview was on Monday” would be 100% understood by another native English speaker in America. In this case one could argue that both are grammatically correct. Technically speaking though, you would use “if the interview were on Monday” and “was” in the case of “The interview was on Monday.”

My understanding is that the subjunctive is used when the chances of the event taking place is really unlikely.

“If I were king, I would probably develop a stutter.”

The chances of me becoming king is 0.

If I was to accept this assignment, I would expect….”

That means I am considering accepting the assignment.

But these are niceties in today’s world of slop-along prose.

“It were” is in the subjunctive mood. “It was” is in the declarative mood. The subjunctive mood is used when you want to talk about possibilty or counterfactuality rather than actuality. The subjunctive seems to be fading out of English, possibly because we have modal auxiliaries (can, could, may, might) that seem to do the job just as well. For the time being, however, “It would be better if the interview were on Monday” is correct; do not replace “were” with “was”.

Some people say that “if it were” signifies a lower likelihood. If you don’t see any difference in meaning between “if it were” and “if it was” then you’re not one of those people. However, “if it were” is also seen as more formal, so if you want to be formal…

subjunctive were

Unpack the main clause of your conditional sentence: ‘it’d be’ stands for ‘it would be,’ which is modal. ‘Were’ is a present subjunctive and ‘was’ a past indicative, each occurring in the ‘if’ clause, which is a subordinate clause. Only the subjunctive is grammatical (though the past indicative passes commonly in conversation).

The use of ‘was’ implies a past statement of fact.

Compare these examples:

‘If I were happy, I would smile.’ (Present)
‘If I were happy, I would have smiled.’ (Past)
‘If I was happy, I smiled.’ (Present)
‘If I am happy, I smile.’ (Past)

The main clause is the second in each pair. Those using a modal auxiliary take a subordinate clause in the subjunctive. ‘Was’ only works for a past definite condition.

Oops! I said declarative when I meant indicative.

@thecardiffgiant A better past counterfactual is “if I had been happy, I would have smiled.”
You got your present and past factuals mixed up.

http://alt-usage-english.org/excerpts/fxsubjun.html

My husband asks me this question over and over again. I hope fluther finally gives us a defintive answer.

@thecardiffgiant If I am happy is the past?

@submariner is correct.

I will be mourning the subjunctive mood in my lifetime, I’m sure.

Yep, Submariner is correct.

That is, “were” is more correct. Many Americans don’t know this, have no idea what subjunctive means, and use “was”.

My husband had decided, when he first started contemplating this, that were must be right, because the song goes, “If I were a rich man…” but then he worried there might have been poetic license when writing the song. Lol.

@JLeslie: No. Tevye implies, by using the subjunctive (which is still alive and well) that he will never be rich.

@gailcalled Right. I see. We, as the audience, understand he will always be poor. Thank you.

If I were dead, I wouldn’t be able to tell you that the subjunctive need not express that some state of affairs that is now counterfactual will always be so.

@gailcalled So if I said “if I was a rich man”, it means the likelihood of me becoming rich is higher than it is if I said “if I were a rich man”?

The first option is correct (or will be once the comma after “though” has been deleted). All three verbs (“would,” “were,” and “could”) are properly in the subjunctive.

I am already mourning the passing of the subjunctive, @absalom. The present subjunctive is all but gone and persists mainly in stock phrases that people are not parsing or conjugating. They have no idea it’s subjective when they say “It’s important that everyone be on time for the meeting.” And fewer and fewer are still saying that.

Oops. “Subjective” ⇛ “subjunctive.”