"One-size" diapers are touted by manufacturers as completely adjustable from birth through potty training. Take this claim with a grain of salt, though, because often times they're just too bulky to fit well on newborns, particularly in the leg area. For most babies, we recommend one-size cloth diapers starting around 10-12 lbs, once your baby's thighs have filled out a bit. If you need ideas for cloth diapering a newborn, check out the newborn diaper rental packages we offer or our selection of specially-sized newborn diapers available for purchase.