Twins will need double the amount of diapers unlike just one baby.
With one baby they typically go through 10 to 12 diapers per day as newborns and as they get older the amount of diapers per day drops down to around 5 to 7 diapers per day.
So then you would need 20 to 24 diapers per day for newborn twin babies and for older twin babies you would need 10 to 14 diapers per day for older twins.
For one baby diapers typically cost from $40.00 to $70.00 per month depending on the brand of diapers and the price of diapers you buy.
So you can expect to pay between $80.00 per month to $140.00 per month for diapers for twins but you might spend a bit more depending on the diapers you buy.
The cheaper diapers you buy the less money you'll pay but I would personally budget at least $140.00 per month for diapers for twins.
However some people have reported that they pay around $200.00 per month for diapers for twins especially as newborns so maybe you should budget at least $200.00 per month for diapers for twins.