The following estimates are based on prices in San Francisco, California.
Disposables - For these calculations, let's assume that a family needs about 60 diapers a week. In the San Francisco Bay area, disposable diapers cost roughly 23¢ per store-brand diaper and 28¢ for name-brand. This averages to 25.5¢ per diaper. Thus the average child will cost about $1,600 to diaper for two years in disposable diapers, or about $66 a month.
Diaper Services - Subscribing to a diaper services costs between $13 and $17 each week depending on how many diapers a family decides to order.
Let's assume the family spends roughly $15 a week for 60 diapers a week. This equals $780 annually and averages to $65 a month. Over the course of two years, the family will spend about $1500 per baby, roughly the same cost as disposables, depending on what type of covers are purchased and what type of wipes are used. If one adds in the cost of disposable wipes for either diapering system, the costs increase.
Cloth Diapers - For cloth diapering, each family will probably need about 6 dozen diapers. The cost of cloth diapering can vary considerably, from as low as $300 for a basic set-up of prefolds and covers, to $1000 or more for organic cotton fitted diapers and wool covers. Despite this large price range, it should be possible to buy a generous mix of prefolds and diaper covers for about $300, most of which will probably last for two children. This means the cost of cloth diapering is about one tenth the cost of disposables, and you can spend even less by using found objects (old towels & T-shirts).
National Costs - According to the U.S. Census Bureau, there were about 19 million children under four in 2000. We could probably assume that there are about 9.5 million children under two and therefore in diapers at any one time. Based on previous studies, we estimate that 5-10% of babies wear cloth diapers at least part time. We will average these figures to 7.5% of babies in cloth diapers and 92.5% in disposables. This means that about 8.8 million babies in the U.S. are using 27.4 billion disposable diapers every year
Based on these calculations, if we multiply the 8.8 million babies in disposable diapers by an average cost of $800 a year, we find that Americans spend about 7 billion dollars on disposable diapers every year. If every one of those families switched to home-laundered cloth prefold
diapers, they would save more than $6 billion, enough to feed about 2.5 million American children for an entire year. Coincidentally, the 2002 U.S. Census reveals that 2.3 million children under 6 live in poverty.
Tax Savings - In some specific circumstances, when cloth diapers have been prescribed for the treatment of a disease, tax savings may be available through the use of flexible spending accounts and medical expense deductions. This could represent a 10% - 35% savings on the cost of diapers depending on the family's tax rate.