Why Confidence Level 95% is -1.65? I'm learning about Value at Risk for Investing which got me into statistical questions.
Here it's said that
For a confidence level of 95%, # of Standard Deviations (σ) = -1.65 x σ
And for a confidence level of 99%, # of Standard Deviations (σ) = -2.33 x σ
My question is, where do we get the -1.65 from? I've googled and found that for investing, the 95% confidence level always uses -1.65 in here, here, and this youtube video.
However when from the answers on this post, you can see that people are sure that -1.65 belongs to a 90% confidence level. Also see this answer.
So which one is correct? And how does it get the number from anyway? (Sorry I did not learn about statistics, please share a source to learn if you have)

The sources you mention assume normal distribution, or use the normal distribution to approximate the underlying distribution. You are probably familiar with the 68-95-99.7 rule, mean $\pm 1.65$ standard deviations covers the middle $90\%$, with $\pm 2.58$ it's the $99\%$. In the links, probably somebody mixed both.
