it goes without saying (that)
(it is) needless to say
I don’t need to remind you
Structure
- Verb + (という) + こと / の + は + 言うまでもない
- い-Adj + (という) + こと / の + は + 言うまでもない
- な-Adj + という + こと / の + は + 言うまでもない
- な-Adj + な + こと / の + は + 言うまでもない
- Noun + という + こと / の + は + 言うまでもない
- Noun + (なの) + は + 言うまでもない
- Phrase + (は) + 言うまでもない
[Used to express something obvious, not surprising. Often used to remind someone or confirm something that should already be known or to add emphasis]
I have a question about this example:
A：「レオンはプロだそうだよ。」
B：「うん、それ は言いうまでもない ね。」
それ is a noun here (hence それなのは〜 also being accepted), so why is それというのは〜 not accepted?
Hey 
To be honest, それというのは言うまでもない is simply not used. It is understandable though.
I hope it helps,
Cheers!
Okay, thanks.
Hello! I noticed a similar example:
さだおさんは中国語がペラペラだ。英語はいうまでもない。
英語 is a noun, but entering こと in the answer is marked wrong. Is there another rule not written in the explanation?
Hey @pandashoujo 
In this case, ことはいうまでもない does not sound natural.
Actually, I decided to change the structure section, so that only Noun + はいうまでもない construction is provided.
It is because Noun + ということは言うまでもない rarely feels natural and in most cases, Japanese speakers would correct it to は言うまでもない so it is better to avoid it.
Sorry for the inconvenience 
An example where it feels natural:
彼っぽいセリフだということはいうまでもない。
Needless to say, this line sounds like him.
彼はかなり人気だ。金持ちということは言うまでもない。
He is quite popular. Not to mention, he is rich.
I see! Thank you for updating the explanation. I think it will help me.
I am a little confused about verbs in this structure, though. Sometimes it seems like they should get こと, sometimes not. Are they considered “a phrase” rather than a verb at times?
By adding こと you are nominalizing what’s before it.
Depending on each sentence, nominalizing what’s before 言うまでもない will make it sound more natural and concise, it’s usually when you have longer sentences rather that one-off words.
You don’t nominalize/use こと if it would be redundant (for example, a sentence that’s already being nominalized by a か or similar nominalizers) or if it’s a single noun.
Read over the example sentences and I’m sure it’ll become clear!
Hope this helps!
As I am learning this grammar point I am constantly amazed that there are sometimes up to 17 ways of phrasing this. Granted a lot of them just differ in the level of politeness but I am curious if there are some forms that are predominately used so that I can focus on some. (My native-level partner said I should just choose one and stick to it but I’d prefer one that is actually commonly used)
For the example sentence「 生きるのに酸素が必要なことはいうまでもない。」would it be unnatural to say 「生きるのに酸素が必要だとはいうまでもない。」?
Would that change the meaning a little to make 「生きるのに酸素が必要」 a quote instead of just stating it as fact?
Thanks 
言わずもがな is a real expression that either means something does not have to be said (like 言うまでもない), or that something is better left unsaid.
言う + negation ず + inclusive も + desire がな.
Thanks! Hadn’t come across がな before, and this phrase isn’t mentioned at all as part of the grammar point…
I expected 助けるべき to still be considered a verb but judging from the accepted answer it’s a な-adjective?
This line of reasoning does make sense, with べき attaching to nouns directly.
But it also can be followed by だ directly, so it doesn’t universally match verb (or な-adjective, or 連体形 for that matter) behavior. There’s more on it here べき (JLPT N3) | Bunpro and here べき - Grammar Discussion - #16 by nekoyama.
So the practical approach here might be to just individually remember all constructions with べき that exist.
