What word/s should I use for 'at least'?
I don't know when to use 至少 and 最少 etc. Can someone explain the difference and give example sentences? Is one more formal than the other?

Question

Answer

最少：一群东西里面，数量最少的。   
    例：        我们每个人都有一些苹果，我拥有的最少。
                     李华有10块钱，小明有13块钱，我有20块钱。我们三个中，李华的钱最少。
至少：比....还要少
   例：        他的身高至少183cm。
                    从我家到公司至少有6km。

Answer

至少 = at least 
最少 = the minimum.

Answer

两个词语的意思非常接近，意思是≥，至少+数词或行为，最少+数词

Answer

Very close to the two words mean，Mean acuity，≥，  至少 + numerals or behavior, 最少 + numerals

Answer

至少 is the right word used for 'at least'
最少 means 'no less than' and 'have the fewest quantity among '

I think in most of cases 至少 could be replaced with 最少 ，they are interchangeable in the examples below.
他的身高 至少/最少 180cm
我家到公司 至少/最少 6km

The example sentence to 最少 as the meaning of "no less than " : 
我手上最少有500元（I have no less than 500 dollars in my hand)

The example sentence to 最少 as the meaning of 'have the fewest quantity among ' :
我擁有的錢是所有人之中最少的（ I have fewest money among folks)

Hope it would help you to tell them apart.