How much money do you need to avoid PDT?

I'm curious, how much capital do you actually need to invest in order to avoid the Pattern Day Trader (PDT) rule? I understand that this rule is in place to protect investors and prevent excessive day trading, but I'm wondering if there's a specific dollar amount that can help me avoid triggering it. Is it a fixed number, or does it vary based on other factors like the types of trades I make or the exchanges I use? Any insights you can provide would be greatly appreciated.