Structure
Number/Amount + Counter + (くらい(1)) + は
Noun + くらい(1) + は
(1) ぐらい
Details
Standard
About Number/Amount + は
The は particle has two primary functions. The first is to mark the topic of a sentence, as learned very early in our Japanese language journey. However, the second common usage of は is to highlight contrast (making a comparison). When は is used after a number/counter, it regularly has this comparison meaning. This can be translated as 'or so', or 'at least'.
Before は, the counter is regularly followed by くらい (or ぐらい). This just softens the statement, and further highlights the 'or so' meaning.
Despite being translated as 'at least', the comparative meaning of は itself is what creates the nuance of this grammar structure. The thing before は is being highlighted as an amount, while also implying that there are other amounts. This implication of another amount makes は sound as if it could mean 'as opposed to (B)'. So in essence, this grammar structure sounds like 'As for (A), as opposed to (B)', where (B) is not usually mentioned.
Antonyms
Related
Vocab Coverage
All Bunpro Vocab that appears on this item.
Examples
There are no sentences available for this content
Hold tight, context sentences are coming soon!
Self-Study Sentences
Online
は = at least?
Japanese StackExchange
Offline
[AIAIJ] An Integrated Approach to Intermediate Japanese
Page 229
Tobira
Page 118
Track Resources!
Bunpro tracks all of the resources you’ve visited, and offers relevant bookmarks of physical books to help with offline tracking.
Number/Amount + は – Grammar Discussion
Most Recent Replies (9 in total)

Fuga
Hey @okayfrog !
The Main difference between these grammar point is that は has the nuance of ‘at least’ while も has the nuance of ‘as much as’ and has the nuance that the speaker is surprised.
For example, the sentence, 彼は昨日4人前ぐらいは食べた (He ate at least four peoples worth of food last night) is just stating the fact that he ate 4 servings while, and in the sentence, 彼は昨日4人前も食べた (He ate as much as 4 peoples worth of food last night), you can see that the speaker is surprised by the fact that he ate as much as 4 peoples worth of food.
I hope that this answers your questions!

okayfrog
I’ll try and keep that in mind, thank you.

killhour
This is what was confusing me - I saw 少なくとも in an earlier sentence and tried to look it up only to find that there is no grammar point for it, and the examples are wrapped up into this. Looking around the internet, it seems like 少なくとも itself means “at least,” regardless of the は. Maybe it should be a separate grammar point?