Remove your bread pan from your breadmaker. Using a one cup (8oz) “liquid” measure, fill your bread pan to the top with water. Count the total number of cups it takes to fill it to the very top rim. Generally speaking, if it holds: up to 9 cups of water = 1 pound loaf pan, over 9 to 11 cups of water = 1-1/2 pound loaf pan, over 11 to 13 cups of water = 2 pound loaf pan, and over 13 cups of water = 2-1/2 pound loaf pan. And while we’re on the subject, generally speaking, 1 lb loaf recipes call for up to 2-1/2 total cups of flour, 1-1/2 lb loaf recipes call for up to 3-1/2 total cups of flour, 2 lb loaf recipes call for up to 4-1/2 total cups of flour and 2-1/2 lb loaf recipes call for up to 5 total cups of flour. Hope you find this information helpful. Warmest Regards, The Breadmaker Guru