Well, then...to make it more comparable, it should look like this:
Reagen- 4.63t
HW- 3.28t
Clinton- 2.4t
W- 8.36t
Obama-10.1t
Trump-7.7t
Biden-3.3t
I used the end of their terms as the measure, so all of the numbers probably should be slightly higher, but this is what comes up using the BLS CPI inflation calculator.
It's also worth noting that the presidential term year doesn't align with the federal budget year, so there's not a neat separation between presidents. It seems likely that some of the stimulus payments authorized under GWB ended up credited to Obama. It's absolutely certain that costs incurred in GWB's 2-front war ended up under Obama. In a similar vein, Clinton likely benefited from military downsizing that started after the fall of the Berlin wall and accelerated with the collapse of the USSR and the end of Desert Storm. We shed about 15% of our active duty personnel between 1989 & 1992, and about another 20% by 2000.