It depends on the size of the pellet. When I used
Hikari Gold pellets, I fed my fish two in the morning and two at night. Not that I use the
NLS small fish pellets, I feed about 6 in the morning and 6 at night because the pellets are so much smaller. This is how I guess but it may not help you If you aren't comfortable with the mectric system.
Large Pellets
Any pellets bigger than 2mm are too large for a betta. You would probably have to break up 2 pellets that size at each feeding to make it safe. So this size would be two pellets a day.
Medium Pellets
If the pellet is 1mm, then it's a good size for bettas and you would feed 2-3 pellets twice a day. But even a King Betta shouldn't need more than six medium size pellets a day. If your fish is bloated or pooping too often, just cut it back to 2 twice a day.
Small Pellets
I wouldn't use a pellet smaller than 0.5mm (which is what I use now) and those I feed 6-8 pellets twice a day. But they are so small that sometimes even 10 will fall in during a feeding. Once it's that small, the number will start to vary from fish to fish. I notice snowy eats a few more than Luigi and neither fish looks fatter than the other and no one looks bloated.
I hope this helps. :)