くらい ②・ほど: the difference
くらい ②N3
Meaning
To the extent that, So…that, About the only thing that...
Past papers
Tested 3 times in past papers
Example
寝ることしか出来ないくらい、疲れている。
I am so tired that I can't do anything but sleep.
ほどN3
Meaning
The more, About, To the extent that, So much… that
Past papers
Tested 2 times in past papers
Example
遅れてごめんなさい。あと１０分程で着きます。
Sorry I'm late. I'll be there in about 10 minutes.
How to tell them apart
For strong degree, 「くらい」 and 「ほど」 can often swap, but 「ほど」 is more formal and heavy.
For 'small' or 'minimum' or a dismissive tone, only 「くらい」 works: 「これくらいで泣くな」 (Don't cry over this little thing).
「～ほど…はない」 (nothing is more... than) only takes 「ほど」.
「ば～ほど」 means 'the more... the more...': 「考えれば考えるほど分からない」 (The more I think, the less I understand).