401k money = pre tax and is invested. 20k in a 401k = 15k after taxes (random example), and how long will it take you to get that money?
Have you been in a real emergency, where you need serious money within minutes, not days? Because that's what an emergency fund is for. If I need 10k for an emergency right now, I have that available via card within seconds or (entirely) in cash as soon as I can get to an ATM or bank. Not to mention I know exactly how much I have available.
To answer your question, these are the points you're missing:
- Money in a 401k is pre-tax. Any money you want to withdraw will cost you taxes.
- You can't put money back in a 401k after withdrawing it. You will lose the tax advantages on that money forever.
- Withdrawing from your 401k before retirement costs you a penalty on top of taxes:
> If you withdraw money from your 401(k) before you're 59½, the IRS usually assesses a 10% penalty when you file your tax return. That could mean giving the government $1,000 or 10% of that $10,000 withdrawal in addition to paying ordinary income tax on that money. https://www.nerdwallet.com/article/investing/early-withdrawa....
- If you take a loan against your 401k, that comes with a lot of conditions and what-ifs. That's not going to help you in a real emergency.
- Using your 401k to get emergency cash is not going to be quick. If your house burns down in 20 minutes from you reading this comment, it would be nice to have money available to make arrangements immediately, rather than waiting until your 401k loan/withdrawal is ready.
The ideal is to max out your 401k and have an emergency fund _on top_ of that. Using your 401k to fund an emergency will come at significant short- and long-term cost. Having a post-tax emergency fund (again, that's _on top_ of the 401k) gives you short-term security without compromising your long-term security.