Annual spending of $50k in today's dollars is $1.25m in today's dollars. If your annual spending stays at $50k for the next 5 years, inflation doesn't really matter to you because your spending is still the same. If your spending goes up by 3-4% a year, your target amount will go up as well.

Assuming your spending for one day in retirement will be the same as it is today (plus inflation), then nothing changes for your calculations.

So for me, my barebones FI target is $24k/yr, or $600k. $1643.86 buys me one day. If that goes up by 3% a year for a few years and my spending is then $26,225/year, I'd need $1796.26 in 3-years-from-now dollars to buy one day.