After entering h=text() the values reported by get(h,'extent') are incorrect.

figure(1)
axis([-1000,1000,-1000,1000])
h=text(500,500,"Some text");
get(h,'units')
ans = data

get(h,'extent')
ans =

   333.333   327.062    58.727    12.542

On my system (with a 4k monitor and "Change the size of text, apps, and other items" set to 150% in Windows 10 Settings) [x,y] is off by a multiplicative factor of approximately (although not exactly) 1.5 and the width by a factor of approximately 3.