The amount of size 1 diapers you should stock up on is 520 size 1 diapers.
The 520 size 1 diapers would be 13 packs at 40 in each pack or 3 to 4 boxes of size 1 diapers with 164 per box.
Babies tend to stay in size 1 diapers for 4 months and the weight range for size 1 diapers is between 8 lbs to 14 lbs.
Babies wearing size 1 diapers use around 8 to 10 size 1 diapers a day.
For size 2 diapers you should stock up on 15 packs of 37 per pack or 4 boxes with 142 per box.
Size 3 diapers you should stock up on 27 packs with around 36 per pack or 7 boxes with 136 per box.
Size 4 diapers you should stock up on around 17 packs with around 23 per pack.
Most babies only need up to size 4 diapers before they are potty trained as size 4 diapers fit babies from 2 to 3 years old.
Size 6 diapers are for toddlers 3 years old to around 4 years old and size 7 diapers are for kids around 5 to 8 years old.