Logical pixels
Multiply the number of physical horizontal pixels (or the number of horizontal characters) by 2 repeatedly until you get a value that is &400 or greater. This is the number of horizontal logical pixels.
Similarly, multiply the number of physical vertical pixels (or the number of character rows) by 2 repeatedly until you get a value that is &300 or greater. This is the number of vertical logical pixels.
This gives the following screen sizes:
Horizontal Chars Pixels Points Double until >=&400 10 80 &050 1280 &500 &050 &0A0 &140 &280 &500 20 160 &0A0 1280 &500 &0A0 &140 &280 &500 32 256 &100 1024 &400 &100 &200 &400 40 320 &140 1280 &500 &140 &280 &500 60 480 &1E0 1920 &780 &1E0 &3C0 &780 64 512 &200 1024 &400 &200 &400 80 640 &280 1280 &500 &280 &500 96 768 &300 1536 &600 &300 &600 100 800 &320 1600 &640 &320 &640 112 896 &380 1792 &700 &380 &700 120 960 &3C0 1920 &780 &3C0 &780 128 1024 &400 1024 &400 &400 140 1120 &460 1120 &460 &460 160 1280 &500 1280 &500 &500 170 1360 &550 1360 &550 &550 192 1536 &600 1536 &600 &600
Vertical Chars Pixels Points Double until >=&300 24 192 &0C0 768 &300 &0C0 &180 &300 25 200 &0C8 800 &3C0 &0C8 &190 &320 32 256 &100 1024 &400 &100 &200 &400 44 352 &160 1408 &580 &160 &2C0 &580 45 360 &168 1440 &5A0 &168 &2D0 &5A0 75 600 &258 1200 &4B0 &258 &4B0 90 720 &2D0 1440 &5A0 &2D0 &5A0
Chars Physical Logical 10x32 80x512 1280x1024 (&500x&400) 20x32 160x512 1280x1024 (&500x&400) 40x32 320x512 1280x1024 (&500x&400) 80x32 640x512 1280x1024 (&500x&400) 32x24 256x768 1024x768 (&400x&300) 64x24 512x768 1024x768 (&400x&300) 112x44 1792x1408 (&700x&580)