94:8 The amount needed to make an eiruv for up to 18 homeowners is about a dried fig – which is like one-third the volume of an egg – per homeowner, excluding the one who made the eiruv and in whose house it resides. He doesn’t need to give a loaf because he actually lives there. For more than 18 homeowners – even if there would be 1,000 of them! – there’s a flat quantity of enough food for two meals which is the same as 18 dried figs or 6 eggs. Some authorities say that it’s like 8 eggs, calculating the volume of the dried fig at 4/9 of an egg. (It’s good to use the larger amount but if one used the smaller amount, it is effective – Mishnah Brurah 368:12.) [Editor’s note: The volume of an egg – a k’beitzah - is twice the volume of an olive – a k’zayis. A k’beitzah is generally accepted to be in the vicinity of 55-60 grams, though opinions differ as to the exact amount.]
94:9 One must not be strict about one of the other residents eating the eiruv. If one is stringent about this, it’s no eiruv. One must therefore be careful not to make an eiruv with something that he needs for his own Shabbos meal.