How much plastic pellets does it take to make 1 kg of filament? (making my own 3D filaments)
If you ignore losses due to production machinery, your one kilogram of pellets will provide you with nearly one kilogram of filament. There may be some small loss of material stuck in the auger and drips from the nozzle and any place you discover plastic that is not on the spool.

How many plastic pellets does it take to make one kilogram of filament? One kilogram plus a bit more. If you are asking about the numerical quantity of pellets, how much does one pellet weigh? Are they large pellets or small pellets?