My Family's Interests:What would it work out to for each load? with washing soda, borax and ivory soap?
Add the price of the bar of soap, divide the cost of washing soda by six (that's about how many cups are in a regular size box), add that, then figure the cost of borax the same way. (There are about eight cups in a regular size box of borax, so divide the price by 16) The rest will depend on how much you use for each load. Some people use only 1 tablespoon. I use a little more.
1 cup of washing soda
1/2 cup borax
1 cup of soap flakes
That makes 2 1/2 cups of detergent. At 16 tablespoons per cup, you'll have 40 loads' worth. Divide your total cost by 40.
Different "recipes" may have different amounts; this is the one I use.