I said need.
I am often asked this question from moms of children of all ages. The number will vary depending on the age of your child.
During the newborn stage, regardless if one uses cloth diapers or disposables, babies go through a lot of diapers. Which is yet another obvious reason why one would choose cloth diapers.
A newborn poops a lot therefore absorbency isn’t as big an issue (except at night). Since the majority of newborns eat on average every 2 hours, you can count on them pooping during or after the feeding. This comes out to roughly 12 diaper changes a day.
If you did laundry every day you’d need 18 cloth diapers. However, that can be cutting it close for most. I recommend at least 24. Often I will suggest 20 to readers but the safe side is 24 if you are washing every other day-ish.
During the night you may or may not choose to change your baby. It’s your call and you’ll know what is best for your baby. For our 1st and 2nd babies I changed them a couple of times at night. For our 3rd I wanted a cloth diaper that would work all night. I had a few systems but it wasn’t until our 4th that I found the best. Sustainablebabyish bamboo fitteds are excellent nighttime diapers even from the very beginning.
Again, your baby might need to be changed every time they pee which would mean a couple (or a few) changes at night. You have to make that decision.
As your baby grows closer to a year they will poop less (usually) and can go without a nighttime change (usually).
From 10m to 15m, they may only need 10 diapers a day at most. If they only use 1 for a 12 hour night stretch then you’d really only need about 8 per day. Most parents don’t like to cut it that close but if money is tight you can make it work.
When we began cloth diapering in 2005 our funds were very limited. I bought 2 dozen prefolds and 6 prorap covers for my 15m old son. I don’t like prefolds but they work well for a newbie who knows nothing else. These diapers were wonderful. I soon learned of other diapers and saved up to buy 4 Happy Heiny’s. These were the bomb! (to a newbie going from prefolds )
I was not interested in using anything but those 4 diapers…so I washed them a LOT. At night I would still use a double prefold/prorap combo. So you can get by with a very small stash.
When your baby is a full-blown toddler they often poop a couple of times a day (again usually) and diaper changes can stretch to every 3-4 hours. I say this, which is contrary to what is “recommended”, because if I change Sterling every 2 hours I’d find a dry diaper most of the time. At 16m, I go through maybe 5 diapers a day.
I use Bum Genius Elementals during the day and usually the diaper is wet but not soaked. To relate this to fluid intake, Sterling drinks about a full sippy cup of goat milk in the morning and throughout the day water as he asks for it or sees it and wants it. He weaned last month (sniff, sniff).
There is no magic number of cloth diapers you will need in your stash. It really depends on your baby’s preferences and how often you desire to do laundry. Some moms wash only once a week, obviously they have a large stash.
I’ve found though that even if you have 40+ diapers (which I’ve had), you really only use your favorite dozen over and over.