You can use a very handy set phrase, 少なくとも【すくなくとも】.
少なくとも works when you talk about a quantity (you may already know this):
- 少なくとも100万円は必要です。 We need at least 1 million yen.
- 少なくとも5年は勉強しなさい。 You must study at least for 5 years.
And it also works when you talk about a situation that is better than something even worse:
- 少なくとも雨は降っていない。 At least it's not raining.
- 少なくとも何もしないよりはいい。 It's at least better than doing nothing.
As you may have noticed, the contrastive-は is often used with this expression. (は on its own can have the meaning of "at least".)
(I answered this question because you seem to be new to this site and it can be seen as a focused phrase-requests, but please always try to include your prior effort/research in your question. Otherwise, it may be closed as an effortless bulk translation request.)