I think I asked the question poorly.

I want my withdrawal rate at retirement of 4% to be $65,000. This, presumably, takes into account yearly 2-3% inflation (which is my current assumption). To get there, I would need $1,625,000 in total investments. According to the Shockingly Simple Math, I *should* be able to achieve that in ~10 years as long as I'm putting away ~$42,000/yr in investments over those 10 years.

Obviously, nothing is perfect and who knows what the market will do. But based on the Shockingly Simple Math that is more-or-less the idea behind the whole thing.

The problem I'm running into in all of the FIRE calculators is they ask for my current income. When I put that number in, I get a wildly different outcome that says it will take a really long time for me to get to that goal. It seems like all those calculators assumes I'm going to live at my current lifestyle and income level into retirement.

So, to clarify my question: Regardless of my income, if I want to withdraw $65,000/yr in FIRE retirement, assuming a 4% withdrawal rate, I should be bale to hit that number in ~10 years as long as I invest 64% of $65,000 (aka $~42,000/yr). This also assumed I am investing in pretty standard index funds for that time.

Am I understanding the math correctly, or to live off of $65,000 in the future do I need to be investing 64% of my current income? It seems like my assumptions above are correct, but almost none of the calculators seem to account for what I'm trying to math out.