How large are ostrich eggs?

about the size of an American football

10 inches

Edited by H. Neeser. Somebody has a shrunken ruler. I have had many Ostrich eggs, and never saw one bigger than 6" X 5". From wikipedia, "on average they are 15 centimetres (5.9 in) long, 13 centimetres (5.1 in) wide, and weigh 1.4 kilograms (3.1 lb), over 20 times the weight of a chicken egg. They are glossy".