Used to mean 'at this rate' or 'if things continue like this' (indicating an expected result given the current situation).
この分だと電車に間に合わないよ。
At this rate, you won't make the train.
この分では予算を超えてしまいそうだ。
At this rate, we might exceed the budget.
彼はこの分だと来週までに終わらないだろう。
If things continue like this, he probably won't finish by next week.