When your baby is a newborn they will usually go through between 9 to 12 diapers per day.
So make sure you have at least 360 or more newborn diapers for the first month.
Then after the newborn age the baby will need to wear size 1 diapers and you'll likely need 300 to 360 diapers per month for the 1 month old baby.
When the baby gets to 6 months of age they may only need 6 to 8 diapers per day and after 1 year old they will usually only need 6 to 7 diapers per day.
As the baby gets older they will usually pee and poop less and will not need as many diaper changes in the day.
The newborn baby will grow out of newborn size diapers within the first month or so.